Science and Management in the Hanalei Watershed: 

A Trans-Disciplinary Approach 

Proceedings from the Hanalei Watershed Workshop 

February 21-22, 2007 

Princeville, HI 

 Edited by Michael E. Field, Carl J. Berg, and Susan A. Cochran 

Open-File Report 2007–1219 

U.S. Department of the Interior 

U.S. Geological Survey 
U.S. Department of the Interior 

DIRK KEMPTHORNE, Secretary 

U.S. Geological Survey 

Mark D. Myers, Director 

U.S. Geological Survey, Reston, Virginia 2007 

Revised and reprinted: 2007 

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Suggested citation: 

Field, M.E., Berg, C.J., and Cochran, S.A. (eds.), 2007, Science and Management in the Hanalei 

Watershed: A Trans-Disciplinary Approach; Proceedings from the Hanalei Watershed Workshop: 

USGS Open-File Report 2007-1219, 87 p. 

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- ii - 
Contents 

Acknowledgements ....................................................................................................................................vi

Introduction .................................................................................................................................................vii

Mike Field and Carl Berg, Workshop Conveners

Coral Disease in Hanalei Bay.....................................................................................................................1

Greta Aeby

History of Water Quality Studies in the Hanalei Bay Watershed ........................................................2

Carl Berg

Tracing Mobile Sediments in the Hanalei Watershed and Bay System: A Geochemical 

Approach .......................................................................................................................................................5

Michael Bothner, Sandra Baldwin, Michael Casso, Amy Draut, Richard Rendigs, Richard 

Reynolds, and Renee Takesue

Spatio-Temporal Patterns in Coral Cover and Coral Settlement on an Exposed Shoreline in 

Hawai`i..........................................................................................................................................................10

Eric Brown and Alan Friedlander

Sediment Porewater Toxicity Study in Hanalei Bay, Kaua`i...............................................................13

Scott Carr and Marion Nipper

Investigating the Use of Remote Sensing for Watershed Landscape Analyses with Applications 

to Water Erosion Vulnerability and Sedimentation in Hawai`i: Hanalei, Kaua`i .............................16

Pat Chavez, Jo-Ann Isbrecht, Rian Bogle, and Miguel Velasco

Distribution of mud in Hanalei Bay, Kaua`i: June vs. September 2006.............................................18

Susan Cochran, Mike Field, and Curt Storlazzi

Seasonal Flood Deposits in Hanalei Bay, Kaua`i, HI............................................................................22

Amy Draut, Mike Field, Mike Bothner, Susan Cochran, Michael Casso, Sandy Baldwin, 

Richard Reynolds, Josh Logan, and Curt Storlazzi

Riparian Composition and Function in a Small Watershed in Hanalei, Hawai`i .............................28

Carl Evensen and Guy Ragosta

Evaluation of a Non-Point Source Pollution Model, AnnAGNPS, in Hanalei Watershed, 

Kaua`i............................................................................................................................................................30

Ali Fares

- iii - 
Photographic Time Series of Sedimentation Near the Wall, Hanalei Bay, Kaua`i, Summers of 

2005 and 2006 ..............................................................................................................................................33

Mike Field, Hank Chezar, and Curt Storlazzi

Resistance and Resilience of a Hawaiian Coral Reef Fish Assemblage to Dynamic Natural 

Conditions: Hanalei Bay, Kaua`i - 1993 to 2005 .....................................................................................36

Alan Friedlanderand Eric Brown

Developing Tools for Assessing Land Based-Contamination Impacts in Corals............................39

Laetitia Hédouin and Ruth Gates

Hydrodynamic Modeling of Hanalei Bay ...............................................................................................41

Ron Hoeke and Curt Storlazzi

Mapping Plant Species and Communities in the Hanalei Watershed..............................................43

Jim Jacobi and Stephen Ambagis

Impact of Sediment, Storm Waves and Storm Floods on Hawaiian Reef Communities ...............45

Paul Jokiel

Submarine Groundwater Discharge in Hanalei Bay: Impacts on Coastal Water Quality.............46

Karen Knee, Blythe Layton, Alexandria Boehm, Joseph Street, Carl Berg, 

and Adina Paytan

Hanalei Bioassessment Survey ...............................................................................................................49

Linda Koch

USDA Natural Resources Conservation Service Assistance to Hanalei.........................................50

Dudley Kubo

Options for the Disposal of Wastewater Effluent in Hanalei, Hawai`i..............................................52

West Marrin

Climate Data Input to Modeling the Hanalei Watershed ....................................................................54

Daniel Moore

Survey of Chemical Contaminants in the Hanalei River, Kaua`i, Hawai`i, 2001 ..............................57

Carl Orazio, Thomas May, Robert Gale, John Meadows, William Brumbaugh, 

Kathy Echols, William Steiner, and Carl Berg

Soil Sampling for Cesium-137 and Observations of Streambank Erosion in the Hanalei River 

Watershed ...................................................................................................................................................59

Paul Pedone

- iv - 
Water Quality Regulation in the Hanalei Bay Watershed...................................................................61

David Penn, Amy King, Andrew Parker, John Craig, and Sen Bai

Magnetic Study of Sediment in Hanalei Bay and the Hanalei River Watershed: Contribution to 

Understanding Sources and Transport of Terrigenous Sediment ....................................................64

Richard Reynolds, Michael Bothner, Carl Berg, Amy Draut, and Harland Goldstein

Geomorphic Assessment of the Hanalei Stream Network Including Preliminary Hydraulic 

Geometry Analysis Results.......................................................................................................................69

Matt Rosener

Applying the Science: Taking Steps to Improve Water Quality and Coral Reef Communities.....71

Hudson Slay, Dave Penn, Katherine Chaston, Wendy Wiltse, and Audrey Shileikis

Summary of the 2006 Update to the Soil Survey for Hanalei Watershed.........................................74

Chris Smith and Katina Hanson

In Situ Measurements of Coastal Circulation and Sediment Dynamics in Hanalei Bay, 

Kaua`i............................................................................................................................................................77

Curt Storlazzi, Kathy Presto, Josh Logan, and Mike Field

Streamflow and Suspended Sediment Load in the Hanalei River.....................................................80

Gordon Tribble and Barry Hill

Appendix 1. Agenda for the Hanalei Watershed Workshop ..............................................................83

Appendix 2. List of Workshop Contributors ...........................................................................................85 

 - v - 
Acknowledgements 

The communities of Hanalei Bay and northern Kaua`i have been overwhelmingly 

supportive of our research studies in the watershed and the bay, and we very much appreciate and 

thank them for their support. Many of our studies could not have been conducted without their 

assistance. In particular, we wish to acknowledge the members of the Hanalei Watershed Hui for 

their major contribution of bringing together scientists and managers from a diversity of 

backgrounds and disciplines; it was indeed the precise approach that was needed to understand the 

complex Hanalei system. We thank the Princeville Resort for making it possible to host this 

workshop in their hotel on the doorstep of Hanalei Bay, a remarkable venue for a remarkable 

watershed. The success of the workshop results from the efforts of many, and we wish to 

acknowledge in particular the masterful organizational skills of Kathleen Donahue. The abstracts in 

this volume benefited from the careful and knowledgeable reviews of David Rubin of the U.S. 

Geological Survey in Santa Cruz, CA, and Katherine Chaston of the University of Hawai`i at 

Manoa, and we thanks them for their time and thoughts. A significant portion of this workshop, 

along with publication of this abstract volume, was made possible by the Coastal and Marine 

Geology Program of the U.S. Geological Survey. 

 - vi - 
Introduction 

Mike Field and Carl Berg, Workshop Conveners 

The results of recent studies in the Hanalei watershed are impressive, both in content and 

breadth. Funded, directed, and/or conducted by investigators from many disciplines from local 

organizations (the Hanalei Watershed Hui), the University of Hawai`i, the State of Hawai`i 

(Department of Health, Department of Land and Natural Resources), and Federal organizations 

(U.S. Department of Agriculture, U.S. Geological Survey, Environmental Protection Agency, 

National Oceanic and Atmospheric Agency), their sum total have contributed markedly to our 

understanding of processes in the watershed. There has been an overwhelming amount of 

information that has been collected in the Hanalei Bay Watershed—from Mt. Waialeale to the far 

reefs—in just the past 5 years. This workshop was initiated to document our collective 

understanding, better integrate our results, and identify the salient issues that remain to be studied. 

To better understand the processes and impacts to the terrestrial and marine ecosystems, we 

fashioned a series of questions that sought to focus the knowledge and expertise of the workshop 

participants on providing understanding of the interplay of processes in the watershed. The topics 

and daughter questions that the group undertook are as follows:

• How sediment is generated in the watershed 

• What is the importance and relative contributions of landslides and stream banks as 

sediment sources, and are the amounts changing in frequency? 

• Do invasive plants and feral ungulates (such as pigs) play a role in the amount of 

sediment released by landslides or overland flow? 

• Is sediment in storage in the valley an important historic source? 

• Where is most of the sediment coming from in the watershed?

• How sediment is transported in the watershed 

• What rainfall or streamflow thresholds generate large sediment fluxes? 

• What transport processes dominate in the valley, and where (debris flows vs. 

channelized flows vs. overland flow)? 

• What are representative bank erosion rates, and what material is entrained?

 - vii - 
• Deposition of sediment in the lower watershed 

• Have historical (and possibly archaeological) alterations to the banks of the Hanalei 

River reduced overbank flow and fine sediment deposition during floods? 

• What are historic deposition rates, and are they comparable to Holocene and 

Pleistocene rates? 

• Has the delta location varied over the Holocene, and how might this affect the reef 

system?

• Deposition of sediment in the bay and beyond 

• What are the pathways of sediment through and within the bay? 

• What is the residence time of flood sediment in the bay? 

• What are the major controls on transport and residence time within the bay? 

• Flow of nutrients and pathogens via groundwater and surface flow 

• Is groundwater an important source of nutrients to the bay? Of pathogens? 

• Are there particular "hot spots" of groundwater discharge along the shoreline and/or 

within the bay? 

• Are there particular "hot spots" of nutrients/pollutants, and do we know the source? 

• What are the circulation patterns and residence times of pathogens, pollutants and 

nutrients in the bay? 

• How terrestrial and aquatic ecosystems have been affected 

• What is the relative health of the Hanalei River ecosystem? 

• What is the relative health of the Hanalei Bay coral and fish populations? 

• Have coral recruitment rates changed in recent years, and if so, do we know the 

cause? 

• What management actions are needed to improve water quality and reduce pollution 

threats to corals? 

• How can we document our present state of knowledge for application to 

management? 

• What science questions need to be addressed for improved decision-making and 

resource management? 

The participants in this workshop were directed to address possible sources of these and 

other pollutants, their effects on the environment, and possible management actions to reduce 

levels of pollution and pollutant loads. As this collection of abstracts illustrates, they did an 

amazing job. The goal is now to determine what further research and collaborations are necessary 

to meet information needs, and how to use this information in making policy decisions for water 

quality improvements for the watershed. 

 - viii - 
Coral Disease in Hanalei Bay 

Greta Aeby1 

Coral disease has contributed to the serious decline of reefs in the Western 

Atlantic and is also emerging as a problem in the Indo-Pacific. In 2004, baseline coral 

disease surveys were initiated in the main Hawaiian Islands and as part of this effort, 

coral disease assessment was added to the Coral Reef Assessment and Monitoring 

Program (CRAMP) protocol at 3 sites within Hanalei Bay. Corals were examined for 

signs of disease along established belt transects for a total of 250 m2 of reef surveyed. 

Corals with lesions were described, photographed and samples taken for follow-up 

histopathological analysis. Signs of disease were found at all three sites with an average 

of 0.027 diseased colonies/m2

 found. Montipora was the dominant coral on the reefs and 

two montiporid diseases were documented including Montipora white syndrome and an 

unusual Montipora banded tissue loss disease, which has not been found elsewhere in the 

Hawaiian archipelago. Heavy sediment stress was evident on the reefs, which might 

explain the occurrence of the unusual disease. Future studies are planned to more fully 

investigate disease within Hanalei Bay. 

 

1

 Hawai`i Institute of Marine Biology, PO Box 1346, Kane`ohe, HI 96744 

 - 1 - 
History of Water Quality Studies in the Hanalei Bay Watershed 

Carl Berg2

In 1998 the Hanalei community came together through the designation of the 

Hanalei River as an American Heritage River, and formed the Hanalei Heritage River 

Hui. The Hui held a series of community meetings and developed a Watershed Action 

Plan. A prime component of that plan was the concern of the community that the waters 

of Hanalei River and Hanalei Bay were polluted and that something should be done to 

make the waters clean (fishable and swimmable under the Clean Water Act). Actions 

were taken to begin volunteer monitoring of the streams, river and bay, and, under the 

auspices of the American Heritage Rivers Initiative, to bring Federal partners together to 

assess pollution in these waters, its causes, and its effect on the stream, estuarine, and 

coral reef biological communities. The U.S. Department of Agriculture’s Natural 

Resources Conservation Service (NRCS) undertook the development of the Agricultural 

Non-Point Source (AGNPS) computer model of erosion and sedimentation in the upper 

watershed. The Hanalei Heritage River Hui incorporated as the non-profit Hanalei 

Watershed Hui (HWH), applied for, and was awarded in 2003 one of the U.S. 

Environmental Protection Agency’s (EPA’s) first Targeted Watershed Initiative grants. 

With this, and additional funding, the HWH partnered with various Federal and 

University scientists in research and mitigation programs. 

Earlier studies of Hanalei Watershed waters by the Hawaii State Department of 

Health (DOH) had shown the waters to be water-quality limited (polluted). The DOH 

data were supplemented by data collected by volunteers and staff of the HWH and 

incorporated in the DOH 2004 303(d) list of impaired waters. Hanalei Bay and Hanalei, 

Wai`oli, Waipa, and Waikoko estuaries were all variously listed as impaired for turbidity 

and/or Enterococcus bacteria, an indicator of fecal contamination. The estuaries were 

given a high priority rating and a Total Maximum Daily Load (TMDL) study was 

recommended for the Hanalei Estuary. This study was undertaken with funding from the 

EPA, is nearly completed. 

As part of the Hanalei Targeted Watershed Initiative, the HWH staff undertook a 

study of the quality of the waters of Hanalei Bay Watershed and presented these data to 

the DOH for the next round of water quality limited designations and for the TMDL 

study. Briefly, HWH believes that the waters do not meet DOH standards for nutrients. 

Values in red in table 1 exceed either geometric mean criteria, or criteria that samples 

exceeded a threshold level greater than 5% or 10% of the time. The U.S. Geological 

Survey (USGS) and Ducks Unlimited (DU) Pond sites are in the freshwater, middle reach 

of the Hanalei River, while the others are in the estuaries of the river or streams. All of 

 

2 Hanalei Watershed Hui, PO Box 1285, Hanalei, HI 96714 

 - 2 - 
the estuaries exceed DOH standards for turbidity (table 2) and the USGS and DU riverine 

sites exceed standards in the dry season (table 3). Enterococcus geometric mean values 

for Hanalei Bay estuaries and water at the Hanalei Pier exceed DOH and EPA standards 

(tables 4). Values for beach waters at Hanalei Pavilion and Pinetrees exceed DOH 

standards (7 cfu/100 ml) but not EPA standards (34 cfu/100 ml). 

Table 1. Comparison of nutrient data from 2003 to 2005. Values indicate the geometric 

mean (ug/L, or micrograms per liter) of 24 monthly samples (TN = total nitrogen; NH4

 = 

ammonium nitrogen; NO3

 + NO2 = nitrate and nitrite nitrogen; TP = total phosphorous; and 

PO4

 = orthophosphate phosphorous). 

USGS DU Hanalei Waioli Waipa Waikoko Criteria 

TN 79.7 110.5 143.6 139.2 116.3 275.8 200 

NH4 3.8 8.4 24.3 24.3 16.9 105.4 6 

NO3+NO2 3.4 3.6 18.3 36.7 8.3 45.5 8 

TP 20.6 26.2 32.3 29.8 25.3 51.4 25 

PO4 3.1 4.8 7.3 7.9 3.3 13.4 na 

Table 2. Sediment data from 2003 to 2005 for various Hanalei estuaries. Values indicate 

the geometric mean of 18 monthly samples. All of the estuaries entering Hanalei Bay 

exceed DOH water quality criteria for NTU (NTU = nephelometric turbidity units; TSS = 

total suspended solids). 

Hanalei Waioli Waipa Waikoko Criteria 

NTU 10.3 6.5 8.2 19.3 1.5 

TSS (mg/L) 12.7 6.9 8.8 18.0 na 

Table 3. Sediment data from 2003 to 2005 for Hanalei River locations. Values indicate the 

geometric mean of 18 monthly samples. Hanalei River at USGS and DU sites exceed DOH 

water quality criteria for NTU for dry seasons. (NTU are nephelometric turbidity units, and 

TSS refers to total suspended solids.) 

USGS DU Mouth % increase 

NTU 4.7 8.5 10.3 119.1% 

TSS (mg/L) 5.4 8.0 12.7 135.2% 

 - 3 - 
Table 4. Comparison of Enterococcus values in mpn/100 ml (most probable number per 100 milliliters) from 2003 to 

LocationType

Total Yearly Enterococcus o/oo Enterococcus o/oo Enterococcus o/oo Enterococcus o/oo Enterococcus o/oo Enterococcus 

Count 90 99 90 99 90 99 89 100 90 101 89 

Geometric Mean 77.2 22.0 21.5 182.2 389.9 373.1 

Max 15,531 2,489 2,359 7,270 24,196 24,196 

Min <10 <10 <10 <10 41 20 

mean ppt 28 33.3 33.5 3.7 1.63 

H. Pier H. Pavilion Pinetrees Weke Waioli Waipa 

Beach Beach Beach Estuary Estuary Estuary 

 - 4 - 
Tracing Mobile Sediments in the Hanalei Watershed and Bay System: 

A Geochemical Approach 

Michael Bothner1, Sandra Baldwin1, Michael Casso1, Amy Draut2, Richard Rendigs1, Richard 

Reynolds3

, and Renee Takesue2 

Knowledge of the source, composition, and fate of sediments transported from the 

Hanalei Watershed to the bay and beyond are necessary to predict impacts on coastal ecology. 

This information is required to evaluate the need for preventative or restorative measures. 

In order to identify tracers of sediments transported from the watershed to Hanalei 

Bay, we have measured three geochemical parameters: radioactive isotope activities, metal 

concentrations, and magnetic properties. The radioactive isotopes 7Be (53-day half-life) and 137Cs (30- year half-life) are present in the system largely from atmospheric deposition on land 

that imprints surface sediment in the watershed. Suspended sediment in the river mobilized by 

floodwaters carries an isotopic signature that is observed in suspended matter and in flood 

deposits in the bay. The isotopes also provide information about the timing of past flood 

events recorded in sediment cores. 210Pbex

4

 (22-year half- life) has both atmospheric and marine 

sources and contributes supporting information about these processes. 

Metal concentrations and concentration ratios are being determined by multi-element 

ICP-MS techniques to characterize the chemical composition of sediments in different 

components of the system, and to identify common chemical relationships between sediment 

sources and sinks. The metal analyses also evaluate present concentrations of potentially toxic 

metals and provide a baseline for future change. The third geochemical parameter consists of 

magnetic properties of sediments throughout this system. These properties, summarized in the 

abstract by Reynolds and others (this vol., p. 63), show promise in characterizing sediment 

from different upland regions of the watershed, as well as providing a traceable signature from 

river suspended matter to sediments in the bay. 

Samples of suspended sediment offshore of the Hanalei River were collected with a 

time series sediment trap (fig. 1) deployed 400 m west of the river mouth (Trap W, 1.3 m 

above bottom at 10 m water depth) from June to September 2006. Figure 2 shows that the 

time-series sediment trap collected material typically at the rate of about 50 g/m2

/day during 4-

day intervals until the flood of August 7, 2006, when the trap collection rate increased to more 

 

1

 USGS Woods Hole Science Center, 384 Woods Hole Road, Woods Hole, MA 02543 

2

 USGS Pacific Science Center, 400 Natural Bridges Drive, Santa Cruz, CA 95060 3

 USGS, PO Box 25046, Denver Federal Center, MS980, Denver, CO 80225 

4

 Excess lead-210 (210Pbex) is the total 210Pb activity level minus the level supported by parent 

isotopes in the uranium decay series. 

 - 5 - 
than 520 g/m2

/day, plugging the trap funnel. An identical trap at the South Central site (Trap 

SC), 800 m southwest of the river mouth, did not show an increase in collection rate at the 

time of this flood event, indicating that the flood-derived plume did not markedly increase the 

sediment collection rate at this location. Measurements of bottom stress and turbidity by 

Storlazzi and others (this vol., p. 76) indicate that the high collection rates at the W site are 

related to river discharge and the rates at the SC site are linked to bottom stress from waveinduced currents. Trap collection rates are not a measure of net sediment accumulation on the 

sea floor. 

The activity of radioisotopes (fig. 3) in samples from Trap W near the river mouth 

show minor changes with time until the flood of August 7. Material collected as the flood 

entered the bay had higher 7

Be and 137Cs and lower 210Pbex activities than in samples prior to the 

flood. The activities in the trapped flood material were similar to activities in a single sample 

of suspended sediment from the river collected on September 6, and provide evidence of the 

direct linkage from the river to the sediment trap at site W. The elevated 7Be and 137Cs 

activities in surface sediments of cores collected from the “Black Hole” near site W extend the 

linkage from the river to the major depositional area in the bay. This conclusion assumes that 

the river sample collected during moderate flow (about 7 m3

/s) on September 6 reflects the 

isotopic signature during the greater flood of August 7 (46 m3/s). 

It is of interest to note that the 210Pbex activities in flood deposits of the Black Hole are 

significantly higher than in the river suspended matter or in trapped flood material. The higher 

values are attributed to scavenging of dissolved 210Pbex that is produced from decay of 226Ra 

dissolved in coastal seawater. The scavenging process illustrated by 210Pbex could be expected 

to operate on sediment-reactive contaminants that are added to the coastal ocean from 

accidental spills from ships, runoff, or from the atmosphere. It outlines a mechanism by 

which dissolved contaminants could be introduced to depositional areas of Hanalei Bay. 

The scavenging process is also illustrated by the distributions of radioactive isotopes in 

time series trap samples (fig. 4) from the site 800 m south west of the river mouth. Samples in 

this trap had the highest 210Pbex among all the samples analyzed in this program. The activities 

of 7

Be and 137Cs generally increase during the deployment with higher and variable activities 

after the August 7 flood. The highest activities of all three isotopes occur during the late 

August – early September time frame when bottom stress and trap collection rates were low. 

Material collected then might have much smaller grain size (higher surface area) and/or higher 

organic carbon that could account for higher scavenging of all the isotopes. Sediment texture 

and organic carbon content of trapped sediment have not yet been determined. 

A preliminary analysis of the metal data indicates that the Ba/Al ratio is a good tracer 

of terrigenous sediment. This ratio is constant in both time-series trap sediments until the flood 

of August 7 (fig. 5). Near the river mouth, flood samples have 50% higher Ba/Al than preflood samples. At the South Central site, the flood and post-flood samples have 19 % higher 

Ba/Al ratio than pre-flood values, interpreted to suggest a slight influence from flood-derived 

sediment at this location. Differences in Ba/Al ratio between the river suspended sample 

collected in September and trapped bay sediments (before and during the August flood) 

suggest different sediment provenance during floods of different intensity in the watershed. 

 - 6 - 
The magnetic properties provide additional tracking information in samples of 

suspended river sediment, in sediment trap samples from the August flood period, and in 

samples from flood layers recovered in cores. The parameters showing similarities among 

sediments in these transitional settings include the absolute and relative abundance of 

magnetite and hematite, and the magnetic grain size. 

These geochemical tools are contributing to the understanding of linkages and timing 

of sediment events on land, in the river, and in the bay. More samples are needed to 

characterize the potential sediment sources in this watershed, and a sampling scheme should 

be in place to collect river suspended matter during major floods. 

A 

B

W

SC 

C 

Figure 1. (A) Location of time series sediment traps W and SC in Hanalei Bay. (B) Image of the 

deployed time series trap at site SC. Trap opening is 20 cm and is positioned 1.3 m above bottom. 

(C) Image of 14 of 21 sampling bottles from site W that contain trapped sediment from June 6, 2006 

until the flood of August 7, 2006 plugged the trap while bottle 14 was in place. 

 - 7 - 
Figure 2. Sediment collection rate in time series sediment traps. Trap W is about 400 m west 

of the Hanalei River mouth. Trap SC is 800 m southwest of the river mouth. Trap W plugged 

during the flood of August 7, 2006. 

Figure 3. Activity of isotopes in time series Trap W. Activities in a sample of TSS and 

colloidal material from the Hanalei River (9.6.06) were: 137Cs: 1.7 and 3.2 dpm/g; 7

Be: 24 and 

36 dpm/g; 210Pbex: 10 and 19 dpm/g (where dpm = radiation counts in disintegrations per 

minute). 

Figure 4. Activity of radioactive isotopes in time series Trap SC. 

 - 8 - 
Ba/Al Ratio in Time Series Trap Samples

0

5

10

15

20

25

30

35

6/1/06

6/8/06

6/15/06

6/22/06

6/29/06

7/6/06

7/13/06

7/20/06

7/27/06

8/3/06

8/10/06

8/17/06

8/24/06

8/31/06

9/7/06

9/14/06

Recovery Date

Ba/Al (ppm/wt%) 

Trap W

Trap SC

River Particulates

TSS

Colloid

Figure 5. Variation of the barium to aluminum ratio in time-series trap samples from Hanalei 

Bay. Ba/Al ratios in river suspended matter (TSS) and the “colloidal” fraction are shown as red 

triangles. The green oval contains samples collected during the August flood period, which 

show a different composition than samples collected during June and July. 

 - 9 - 
Spatio-Temporal Patterns in Coral Cover and Coral Settlement on an 

Exposed Shoreline in Hawai`i

Eric Brown1 and Alan Friedlander2,3 

Hanalei Bay, Kaua`i is situated in a dynamic and relatively harsh environment that at 

times includes high wave energy, heavy fresh water influx, and high turbidity. Coral cover 

along 20 permanent transects was assessed using photoquadrats (1993), digital video transects 

(1999), and digital still photographs (2004, 2005). Random points were projected on the 

images to generate percent cover of substrate types. Around Hanalei Bay, overall coral cover 

was low (ca. 14%) and dominated by encrusting forms adapted to high wave energy. Shallow 

sites with greater wave exposure had the lowest coral cover. Sites along edge habitats with 

greater protection from large surf had higher coral cover. The five most abundant coral species 

in 1993 were Montipora patula (7%), M. capitata (2%), Porites lobata (2%), P. compressa 

(1%), and Pocillopora meandrina (1%). Average percent coral cover increased non-linearly in 

Hanalei Bay. Between 1993 and 1999 there was an increase of 5% absolute (34% relative) 

from 14% to 19%. From 1999 to 2005 coral cover remained relatively stable. Much of the 

initial increase was attributed to Montipora patula, which increased in percent cover from 7% 

in 1993 to 11% in 2005. Species composition patterns remained similar during that time 

period. 

Settlement plates were deployed and retrieved from 2003 to 2005 to estimate 

settlement of coral larvae during the annual spawning events. Coral settlement was higher in 

the outer bay than in the inner bay. Coral recruits were dominated by the genus Montipora that 

typically has high recruitment rates but low survival compared to other coral genera. Temporal 

patterns in coral settlement corresponded negatively to Hanalei river flow and wave activity. 

A similar larval settlement study conducted concurrently on a wave-exposed, north shore reef 

community at Moloka`i had significantly lower larval settlement than what was documented at 

Hanalei Bay. Larval settlement around Hanalei Bay was also higher compared to other regions 

around the world and may help explain the increase in coral cover observed over the past 

decade. Temporal variability, artificial substrate type used, or observer biases, however, could 

all affect documented settlement patterns, therefore these patterns may not directly influence 

increases in coral cover. 

 

1

NPS, Kalaupapa National Historical Park, PO Box 222, Kalaupapa, HI 96742 2

 NOAA, National Ocean Service, National Centers for Coastal and Ocean Science, 

Biogeography Team 

3

 The Oceanic Institute, 41-202 Kalanianaole Highway, Waimanalo, HI 96795 

 - 10 - 
Hanalei Bay is one of the few areas in Hawai`i that has shown an increase in live coral 

cover over the past decade. Natural factors such as large wave events are thought to be more 

important in structuring the coral reef community of Hanalei Bay than anthropogenic factors, 

and this may help to explain the trends observed in this study. 

Figure 1. Average coral settlement rates (No. m-2 3 months -1) at each of the sites from 2003 to 

2005. Nearly 99% of the settlement was composed of Montipora spp. Note the different Y-axis 

for the Hanalei site chart. Error bars are ± 1SE. 

 - 11 - 
Figure 2. Change in percent coral cover by species in Hanalei Bay, during the different 

sampling periods. Error bars are ± 1SE.

 - 12 - 
Sediment Porewater Toxicity Study in Hanalei Bay, Kaua`i 

Scott Carr1 and Marion Nipper2

Toxicity tests are commonly conducted as a measure of the bioavailability of toxic 

chemicals to biota in an environment. Chemical analyses alone are insufficient to determine 

whether contaminants pose a threat to biota (Carr and Nipper, 2003). Porewater toxicity tests 

can provide ecologically relevant data on sensitive life stages of a variety of species to a broad 

range of contaminants (Carr and Nipper, 2003). The inclusion of porewater toxicity testing as 

an additional indicator of sediment quality provides a more comprehensive picture of 

contaminant effects in sensitive habitats. In this study purple-spined sea-urchin (Arbacia 

punctulata) fertilization and embryological development porewater-toxicity tests were used to 

evaluate the sediments from the coastal environment around Hanalei Bay, Kaua`i, Hawai`i. 

These tests have been used previously to assess the bioavailability of contaminants associated 

with sediments in the vicinity of coral reefs (Carr and Nipper, 1998; Carr and others, 2001; 

Nipper and Carr, 2000, 2001). 

As part of the Hanalei Bay Watershed study, sediment porewater samples were 

collected in situ at 11 sites in the Bay and at a reference site at Ke`e Beach (station 6) during 

the last week of August, 2005. Six of the samples were collected near shore in a water depth 

of approximately 2 m, whereas the other six samples were collected at depths ranging from 5 

to 15 m. The porewater samples were collected using a diver-deployed syringe connected to a 

filtering medium, with ~500 ml of pore water collected per site. The porewater samples were 

kept at 4oC until they were transported back to the USGS Marine Ecotoxicology Research 

Station in Corpus Christi, Texas, where they were centrifuged for removal of particles and 

used in toxicity tests. The porewater samples were tested in a dilution series design using 20 

ml glass scintillation vials as exposure chambers. Both the sea-urchin fertilization and 

embryological development tests were performed as these tests often show different responses 

to various contaminants with different mechanisms of toxicity. The results from the Hanalei 

Bay pore water were compared with pore water from the reference site in Kaua`i (station 6, 

fig. 1) and from a reference site in Aransas Bay, Texas. Significant toxicity was observed at 

three stations (8, 10 and 12) with the fertilization endpoint but no samples were toxic in the 

embryological development test (fig. 1). The concentration of ammonia and sulfide in the 

porewater samples was below the concentrations known to cause an effect in these tests. 

Toxicity identification evaluation (TIE) studies (Burgess and others, 1996) are recommended 

to determine what substances or classes of compounds are responsible for the observed 

toxicity. With the information obtained from a TIE study it may be possible to identify the 

 

1

 USGS Marine Ecotoxicology Research Station, 6300 Ocean Dr., Ste. 3200, Corpus Christi, 

TX 78412 

2

 Texas A&M University, Center for Coastal Studies, 6300 Ocean Dr., Ste. 3200, Corpus 

Christi, TX 

 - 13 - 
source of the primary contaminants of concern and reduce the inputs of these toxicants into 

this ecosystem. 

Figure 1. Toxicity test results for samples taken in Hanalei Bay, Kaua`i, Hawai`i. Color 

differentiation of the circles indicates level of toxicity observed in the sea-urchin fertilization 

test. There were no toxic samples observed for the sea urchin embryological development test. 

 - 14 - 
Literature Cited 

Burgess, R.M., Ho, K.T., Morrison, G.E., Chapman, G., and Denton, D.L., 1996, Marine 

toxicity identification evaluation (TIE): U.S. Environmental Protection Agency, 

Washington, DC, Phase I guidance document, EPA/600/R-96/054, 70 p. 

Carr, R.S., and Nipper, M., 1998, Preliminary survey of sediment toxicity in the vicinity of 

Honolulu, Hawai`i: Internal report to U.S. Geological Survey, Menlo Park, CA, 18 p. 

Carr, R.S., and Nipper, M. (eds.), 2003, Porewater toxicity testing; Biological, chemical, and 

ecological considerations: Society of Environmental Toxicology and Chemistry (SETAC), 

Pensacola, FL, 346 p. 

Carr, R.S., Nipper, M., and Plumlee, G.S., 2001, A preliminary survey of marine 

contamination from mining-related activities on Marinduque Island, Philippines; Porewater 

toxicity and chemistry; Results from a field trip October 14-19, 2000: U.S. Geological 

Survey Open-File Report 01-441, 19 p. [http://geology.cr.usgs.gov/pub/open-filereports/ofr-01-0441] 

Nipper, M. and Carr, R.S., 2000, Toxicity testing of sediment pore water from the Flower 

Garden Banks, Gulf of Mexico: Final report prepared for the Center for Coastal Studies, 

Texas A&M University-Corpus Christi, Corpus Christi, TX, 7 p. 

Nipper, M., and Carr, R.S., 2001, Porewater toxicity testing; a novel approach for assessing 

contaminant impacts in the vicinity of coral reefs: Bulletin of Marine Science, v. 69, p. 407-

420. 

 - 15 - 
Investigating the Use of Remote Sensing for Watershed Landscape 

Analyses with Applications to Water Erosion Vulnerability and 

Sedimentation in Hawai`i: Hanalei, Kaua`i 

Pat Chavez1, Jo-Ann Isbrecht1, Rian Bogle1, and Miguel Velasco1

A main objective of this project is to investigate the use of remotely sensed satellite 

and airborne image data, along with field-based instrumentation, to detect, map, and monitor 

parameters that are important to help determine the vulnerability of the landscape to water 

erosion and it’s potential impact on critical habitats, with special emphasis on coral reefs. The 

main study sites for the project are on south Moloka`i and the Hanalei watershed on north 

Kaua`i. 

The work at Hanalei includes: 

• The use of Quickbird satellite images, which have 0.6m and 2.4m pixels, to investigate 

vegetation mapping (see Jacobi and Ambagis, this vol., p. 42), vegetation cover and 

sheltering of the soils, and vegetation change detection. 

• Experiment with the use of our airborne digital-camera system, turned sideways, to 

image very steep cliffs to see if this type of imaging can be used to help identify and 

map the vegetation on such difficult to access terrain (with Jim Jacobi). 

• Use of multi-temporal Quickbird satellite images to detect and map existing and new 

landslides within the Hanalei watershed, and to determine their role sediment source 

within the watershed. 

• Investigating the use of a field instrument developed for the remote sensing 

community (spectral radiometer) to see if it can be used to monitor the amount of 

sediment being transported by the Hanalei River into the bay. If successful, such a 

relatively low-cost instrument could be used to monitor different parts of a watershed 

and help determine, to a first order or relative amounts, the sediment contribution from 

different parts of a watershed (with Barry Hill and Carl Berg). 

• Investigate the use of Quickbird satellite and airborne imaging to detect and monitor 

the amount and spatial distribution of suspended sediment concentration levels within 

the taro fields and the nearby Hanalei River. We want to determine if these types of 

data could be used to detect and monitor suspended sediment loads in the taro fields 

 

1

 USGS Southwest Geography Science Team, 2555 N. Gemini Dr., Flagstaff, AZ 86001 

 - 16 - 
and the contribution to the total amount of sediment going into the bay (with Carl 

Berg). 

Note: these same data may be useful to help map and monitor critical bird habitats within the 

lower part of the watershed, including in and around the taro fields. 

Upper Left: Portion of a Quickbird satellite image showing an area at the lower end of the 

watershed with potentially stressed vegetation. 

Upper Right: Portion of a Quickbird satellite image showing a relatively new landslide on the 

upper portion of the watershed (green). 

Lower Left: A photo showing the spectral radiometer mounted close to the traditional USGS 

water gage station on the lower end of the Hanalei River. 

Lower Right: Portion of a Quickbird satellite image covering the FWS taro fields. The image 

data have been classified to display the potential levels of suspended sediment concentration 

(SSC).

 - 17 - 
Distribution of mud in Hanalei Bay, Kaua`i: June vs. September 2006 

Susan Cochran1, Mike Field1, and Curt Storlazzi1

An experiment was conducted to determine the amount of mud versus sand in various 

locations of Hanalei Bay during the summer of 2006 with two questions in mind: (1) is there a 

gradient or any apparent pattern to the distribution? and, (2) what is the overall gain or loss over 

the course of the summer? 

Sediment was hand-sampled in June and September 2006 by divers using 20 cm-long 

push-cores. The sediment from each short core was wet-sieved and dried, and weight of sand 

versus weight of mud was determined. In general, the sand-sized fraction of the samples was 

predominantly carbonate sand, while the mud component was typically dark, terrigenous 

material. 

Figures 1 and 2 show the percentage of mud versus sand for samples collected in June 

and September 2006, respectively. The highest amounts of mud (up to 94% in June) were found 

in samples collected near the “Wall” where the mouth of the Hanalei River cuts across the reef 

flat and enters the bay. Not surprisingly, high amounts of mud (up to 89% in June) were also 

found in samples collected from what is known as the “Black Hole.” Samples collected from the 

middle of the bay and from the western side of the bay were relatively mud-free and consisted of 

nearly 100% clean, carbonate sand. 

Figure 3 shows the difference of mud percent from June to September 2006. Samples 

from the Black Hole had the highest increase of mud over the summer period, possibly due to 

terrestrial input from Hanalei River during summer floods. However, samples collected from the 

middle of the bay show a decrease in mud from June to September. The loss of fine sediment 

from the middle of the bay may have resulted from wave-driven remobilization (see Storlazzi 

and others, this vol., p. 76). 

Overall, the patterns of mud distribution confirm the isotope measurements made by 

Draut and others (this vol., p. 22). Mud entering the marine system from discharge by the 

Hanalei River is primarily deposited along the eastern rim of the bay near the river mouth. 

Residence time of mud in this locale can be long (months to years), as it is apparently only 

slowly reworked and transported out of the bay. In contrast, we infer that the center and western 

portions of the bay are areas of minimal deposition (bypassing) or short residence time due to 

higher reworking rates caused by higher wave stresses. 

 

1

 USGS Pacific Science Center, 400 Natural Bridges Dr., Santa Cruz, CA 95062 

 - 18 - 
Figure 1. Image of Hanalei Bay showing sample locations and percent mud of samples collected 

in June 2006. 

 - 19 - 
Figure 2. Image of Hanalei Bay showing sample locations and percent mud of samples collected 

in September 2006. 

 - 20 - 
Figure 3. Image of Hanalei Bay showing the difference of mud percent from June to September 

2006. The boundaries of the mapped results are limited by the actual data points used for the 

interpolation. 

 - 21 - 
Seasonal Flood Deposits in Hanalei Bay, Kaua`i, HI

Amy Draut1, Mike Field1, Mike Bothner2, Susan Cochran1, Michael Casso2, Sandy Baldwin2, Richard 

Reynolds3

, Josh Logan1, and Curt Storlazzi1

Sedimentary facies, short-lived isotopes 7Be and 137Cs4, and magnetic properties of 

sediment cores in Hanalei Bay, Kaua`i, HI, were used to assess spatial and temporal patterns of 

sediment deposition associated with seasonal flooding of the Hanalei River over two years. 

Sediment cores were collected from the seafloor within Hanalei Bay in early and late summer 

2005 and 2006 (fig. 1). 

The Hanalei River delivers terrigenous sediment and organic matter to reef-lined Hanalei 

Bay. The youngest and thickest terrigenous sediment (recognizable by its short-lived isotope 

activity, sedimentary facies, and magnetic properties) was observed on the east side of the bay: 

near the Hanalei River mouth and in a bathymetric depression known locally as the Black Hole 

that acts as a temporary sediment sink. During this two-year study, the largest flood events 

occurred between February and April 2006, when the Hawaiian Islands experienced sustained 

heavy rainfall, and abundant terrestrial runoff entered Hanalei Bay (fig. 2); we focus here 

primarily on data collected in the second year of the study. Data from the first year of the study 

were published by Draut and others (2005). 

The winter 2006 floods provided the largest amount of terrestrial deposits in the bay 

during this study, leaving flood deposits in the eastern bay that, by June 2006, were on the order 

of 10 cm thick (fig. 3; deposits were thickest in the Black Hole). Abundant wood and organic 

debris were also deposited on the sea floor in the eastern bay near the river mouth, in the Black 

Hole and along the eastern reef wall. The winter 2006 flood deposits have high 7

Be activity, finer 

grain size, a lower proportion of carbonate, and contain abundant terrestrial plant matter 

compared with marine sediment in the cores. Cores collected farther from the river mouth were 

dominated by carbonate sand with little or no 7Be as of June 2006; carbonate facies were typical 

at Stations B, D, E, and H (fig. 1) each time they were cored. Preliminary mass-balance 

calculations indicate that between 13 and 20 percent of the terrestrial sediment delivered to the 

 

1

 USGS Pacific Science Center, 400 Natural Bridges Dr., Santa Cruz, CA 95060 2

 USGS Woods Hole Science Center, 384 Woods Hole Rd., Woods Hole, MA 02543 

3

 USGS, PO Box 25046, Denver Federal Center, MS 980, Denver, CO 80225 

4

 Activity levels of 7Be and 137Cs are commonly analyzed in shallow marine cores to identify 

terrestrial sediment recently delivered to the ocean. 7Be is a naturally occurring isotope with 53-

day half-life, formed in the atmosphere by cosmic-ray spallation of nitrogen and oxygen. It 

becomes associated with vegetation and soil and is concentrated in terrestrial sediment carried to 

the ocean by river discharge. 7

Be remains detectable for up to five half-lives (~8 months). 137Cs is 

an anthropogenic (bomb-derived) isotope with non-constant source function and 30-year halflife. Measurable 137Cs indicates that sediment has been in contact with an atmospheric or fluvial 

source more recently than the 1950s, when this isotope first entered the environment. 

 - 22 - 
bay by the Hanalei River between September 2005 and June 2006 remained in the bay as of early 

June 2006. 

A Hanalei River flood occurred on August 7, 2006, that was smaller than floods the 

previous winter but still a substantial discharge event for the summer season (fig. 2). Terrestrial 

sediment delivered by that flood was apparent in the Black Hole as of September 2006 but little 

sedimentary and isotopic evidence of the summer flood was present elsewhere in the bay by 

September. Stations A and I (both located in the Black Hole; fig. 1) were the only two sites at 

which 7

Be inventory in September 2006 was higher than could be accounted for simply by decay 

of the 7Be inventory that was present at those locations in June 2006. Stations A and I showed 

factors of 3 and 1.2, respectively, elevation in 7

Be inventory in September above the expected 

value from decay of the June inventory. This indicates the presence of new terrestrial sediment at 

those two sites, most of which presumably resulted from the flood on August 7. This 

interpretation is supported by magnetic studies that suggest somewhat different sediment sources 

for the winter and summer flood events. 

Deposits from the winter 2006 floods continued to dominate the sedimentary record in 

the eastern bay through early fall, even after the addition of newer sediment in the August 7 

flood. This high level of sedimentation is consistent with the much higher sediment input of the 

winter floods compared with the August 7 flood (fig. 2). Peak daily water discharge in the largest 

winter flood (February 21, 2006) was a factor of 2.6 greater than that of the August 7 flood, 

whereas sediment concentration on that winter flood day exceeded the sediment concentration on 

August 7 by a factor of 5.9. Although it is common for sediment concentration to increase 

exponentially with water discharge in the rating curves of most streams, the very elevated 

sediment concentrations in the winter floods may have occurred in part because the Hanalei 

drainage basin responded differently to the prolonged winter rain than to the more episodic 

summer rain, perhaps producing additional sediment in the winter by landslides and other masswasting processes. 

Sediment accumulating in the open center of the bay and on its fringing reefs is most 

readily remobilized and advected out of the bay during winter, when oceanographic conditions 

are energetic. In summer, wave and current measurements made concurrently with this study 

(Storlazzi and others, 2006) showed weak currents (~1 cm/s near the bed) and little wave energy, 

indicating that sediment delivered during summer floods most likely remains in the bay until 

winter storms can remove it. Increased turbidity and sedimentation on corals resulting from 

floods of the Hanalei River (as was documented by a camera station in the eastern bay in 

summer 2006) could affect the sustainability of coral reefs and their many associated species. 

This is a particular concern during summer months when wave energy is low and sediment is not 

readily remobilized and advected out of the bay. As shown by our mass-balance estimates for 

June 2006 above, however, even winter flood sediment can persist in the bay for months if the 

wave climate is not energetic enough to transport sediment into the open ocean. 

 - 23 - 
Figure 1. Locations of sediment-core sites in Hanalei Bay: yellow circles identified by station 

letter (A–I). Red circles indicate the locations of oceanographic instrument packages deployed 

during summer 2005 and 2006 (see Storlazzi and others, 2006 for complete description of 

abbreviations and instrumentation; the CRAMP site is one used by University of Hawai`i’s Coral 

Reef Assessment and Monitoring Program). Bathymetry in this image has been interpolated from 

SHOALS lidar data; dark-blue areas indicate no bathymetric data. The isobath interval is 5 m. 

 - 24 - 
Figure 2. A. Water discharge from the Hanalei River. Data were measured at USGS gaging 

station number 16103000 (“Hanalei River near Hanalei”, located 9.2 km upstream from the river 

mouth) and were provided by the USGS Pacific Islands Water Science Center in Honolulu, 

Hawai`i [http://hi.water.usgs.gov/]. This hydrograph spans water years 2004–2006 (September 1, 

2003 through September 30, 2006) with times of core collection indicated. B. Precipitation (cm) in 

the Hanalei River drainage basin recorded at two USGS rain gages. C. Fluvial sediment load (in 

metric tons per day) based on a rating curve and suspended-sediment samples analyzed by the 

Water Resources Division of the USGS. D. Suspended-sediment concentration in the Hanalei 

River measured at USGS gaging station 16103000. 

 - 25 - 
Figure 3. Sedimentary facies, grain size, percent carbonate, and isotope activity at Station I in June 2006. Activitie

excess 210Pb, all decay-corrected to the date of sample collection, are shown in disintegrations per minute (dpm) pfree sediment. This site is located at the north end of the Black Hole, in eastern Hanalei Bay. Much of this core cosediment, which is identifiable from its low percent carbonate (high mud) content and abundant terrestrial organi

between ~12 and 27 cm is more dominantly marine than the rest of the core, with a higher proportion of carbonate ~12 cm of this core comprise a recent flood deposit, containing high levels of 7Be and unconsolidated mud and or

sediment, inferred to have been deposited by the large floods between February and April 2006, was detectable d

cm (based on the 7Be profile), having mixed with more carbonate-rich marine sediment. 

 - 26 - 
References 

Draut, A. E., Field, M. E., Bothner, M. H., Logan, J. B., Casso, M. A., Baldwin, S. M., and 

Storlazzi, C. D., 2006, Coastal Circulation and Sediment Dynamics in Hanalei Bay, Kaua`i, 

Hawai`i, Part II, Tracking Recent Fluvial Sedimentation: Isotope Stratigraphy Obtained in 

Summer 2005. U.S. Geological Survey Open-File Report 2006-1125, 52 p. 

[http://pubs.usgs.gov/of/2006/1125] 

Storlazzi, C.D., Presto, M.K., Logan, J.B., and Field, M.E., 2006, Coastal circulation and 

sediment dynamics in Hanalei Bay, Kaua`i. Part I: Measurements of waves, currents, 

temperature, salinity and turbidity: June–August, 2005, U.S. Geological Survey Open-File 

Report 2006-1085, 35 p. [http://pubs.usgs.gov/of/2006/1085] 

 - 27 - 
Riparian Composition and Function in a Small Watershed in Hanalei, 

Hawai`i 

Carl Evensen1 and Guy Ragosta1

Riparian areas have not been adequately studied in Hawai`i or other island ecosystems. 

Study of composition and function of riparian vegetation is needed to assess the influence of 

riparian areas on water quality, hydrology, and pollutant transport, and to guide sustainable 

watershed management. Riparian vegetation and associated soil and water-quality parameters 

have been characterized for Waipa Stream, a small watershed in Hanalei, on the northern coast 

of Kaua`i. Data collected from 2004 to 2005 include plant species composition, stem diameter, 

canopy and groundcover, as well as stream turbidity, dissolved oxygen and Enterococcus 

bacteria concentrations. Riparian vegetation and soils were characterized in twenty-four plots 

along stratified sections of Waipa Stream, along with two major tributaries that flow into 

upper-and mid-Waipa Stream, and a lower floodplain cattle-pasture diversion ditch. We 

characterized vegetation by measuring stem diameter, using a densitometer for canopy cover, 

and a modified pin-drop method for ground cover. Site conditions were assessed with 

chemical analysis of surface soils and background soil Enterococcus and E. coli levels. 

Weather stations were installed at upper and lower portions of the watershed. In-stream 

temperature gauges were deployed at the beginning and end of each vegetation community 

along the stream, and at the confluences of the tributaries above the stream entrance. At these 

locations we tested water quality for Enterococcus levels, streamflow, turbidity, EC, DO, and 

salinity at specified dates. 

The Waipa watershed riparian areas are dominated by alien species, which were 

differentiated into four major vegetation communities, which differ significantly in species 

composition, canopy, and ground cover. Lower Waipa stream is significantly lower in canopy 

cover than Kolopua tributary. Basal area in the Kapalikea tributary is significantly lower than 

in mid- Waipa stream riparian communities, which are dominated by dense Mangifera indica

and numerous Psidium cattleianum plants. Zingiber zerumbet ground cover is significantly 

higher in summer 2004 than winter 2005, while the reverse is true for Christella dentata. Over 

all areas studied, invasive species significantly dominate ground cover, basal area, and canopy 

cover. Enterococcus levels and turbidity decrease while dissolved oxygen increase in streams 

with increasing elevations in the watershed. Distribution and density of domestic cattle and 

feral pigs seem to be directly related to water quality impairment. 

 

1

 University of Hawai`i, College of Tropical Agriculture and Human Resources, Dept. of 

Natural Resources and Environmental Management, 1910 East-West Rd., Sherman 101, 

Honolulu, HI 96822 

 - 28 - 
Acknowledgements 

This research has been accomplished with support from the USDA CSREES Water 

Quality program, along with strong partnerships with NRCS, Regional Land Grants 

(Universities of Nevada and California), and with faculty from the University of Hawai`i 

WRRC, Sea Grant Extension and the Botany Department as well as in-kind support and 

assistance from the EPA funded Hanalei Watershed Initiative and a community group, the 

Waipa Foundation. 

 - 29 - 
Evaluation of a Non-Point Source Pollution Model, AnnAGNPS, in 

Hanalei Watershed, Kaua`i

Ali Fares1

Impaired water quality caused by human activity and the spread of invasive plant and 

animal species has been identified as a major factor of degradation of coastal ecosystems in 

the tropics. The main goal of this study was to evaluate the performance of AnnAGNPS 

(Annualized Agricultural Non-Point Source) watershed model, in simulating runoff and soil 

erosion in a 50 km2

 watershed located on the island of Kaua`i, Hawai`i. The model was 

calibrated and validated using 2 years of observed stream-flow and sediment-load data. 

Alternative scenarios of spatial rainfall distribution and canopy interception were evaluated. 

Initially, the model produced high CN values, which resulted in increased simulated 

runoff (CN is a curve number used to estimate run-off based on soil and cover type). To 

overcome this problem the initial CN values were reduced to their lower-limit values for the 

corresponding land cover types. Simulations showed that in order to account for canopyinterception effect, a site-specific canopy interception model was preferable over the 

algorithm provided in AnnAGNPS. Accurate representation of the spatial distribution of 

precipitation is critical for accurate model performance. It was demonstrated that even with 

limited number of climate stations within the watershed, an adequate representation of spatial 

rainfall distribution could be achieved using an accurate annual precipitation map. Monthly 

runoff volumes predicted by AnnAGNPS compared well with the measured data (R2 = 0.90), 

however up to 60% difference between the actual and simulated runoff were observed during 

the driest months (May and July). Prediction of daily runoff was less accurate (R2 = 0.55). 

During sensitivity analysis it was found that predicted sediment yield from the 

watershed was closely related to: vegetation root mass, average canopy fall height, soil 

erodibility, percentage of ground residue cover, and canopy cover ratio. The latter two 

parameters had the greatest influence on sediment yield. The entire watershed was covered by 

dense vegetation, which protects the soil from direct rainfall impact. Under these conditions 

high sediment yield was observed on areas with low clay content and on steep slopes. RUSLE 

erosion factor K, which is directly related to soil properties, was the single most important 

parameter which influenced spatial variability of sediment losses. Predicted and observed 

sediment yield on a daily basis were moderately correlated (R2

 = 0.5). For the events of small 

magnitude, the model generally overestimated sediment yield, while the opposite was true for 

larger events. Total monthly sediment yield varied within 50% of the observed values, except 

for May 2004. It was found that approximately one third of the watershed area had low 

 

1

 University of Hawai`i, College of Tropical Agriculture and Human Resources, Dept. of 

Natural Resources and Environmental Management, 1910 East-West Rd., Sherman 101, 

Honolulu, HI 96822 

30
sediment yield (0-1 t ha-1

 y-1), and presented limited erosion threat. However, five percent of 

the area had sediment yields in excess of 5 t ha-1 y-1 (tons per hectare per year). Fifty one 

percent of the total area of the watershed contributed with less than 10% of total sediment 

generated; however, 49% of watershed generated over 90% of the total sediment (fig. 1). The 

results are based on the use of original NRCS soil classification and USGS land cover map 

with baseline curve numbers. 

Figure 1. Total sedimentation contribution versus percent area of watershed contributing to 

the sediment load. 

The model was re-calibrated due to the availability of an updated NRCS soil 

classification and a higher resolution and species-specific land-cover map developed by USGS 

(see Jacobi and Ambagis, this vol., p. 42). Predicted runoff and sediment load using the new 

parameters were more accurate compared to those estimated with the original soil 

classification and Landsat land-cover map. For 2003, predicted runoff and sediment were over 

99% of the measured values. The re-calibrated input parameters were used to predict runoff 

and sediment for 2004 as well. The USGS land cover map with the updated soil classification 

produced slightly overestimated runoff and sediment load. 

In Hanalei, feral pigs are one of the major causes of pollution. The soil disturbance due 

to their activities in the watershed results in increased sedimentation in the coastal areas. The 

implementation of feral pig damage estimates resulted in substantial increase of sedimentation 

due to the high sensitivity of the model to the surface residue cover parameter. 

 Figure 2 illustrates the predicted pig-damaged areas in the Hanalei watershed. An area 

with 40% surface cover disturbed is labeled high pig disturbance, 20% disturbed is light, and 

5% disturbed is trace. Approximately 42% of the watershed’s surface cover has high pig 

disturbance, 37% with light pig disturbance, and 9% with trace pig disturbance. 

31
Figure 2. Feral pig disturbance in Hanalei Bay Watershed. 

With nearly 90% of the study area affected by feral pig activity, predicted 

sedimentation was 4,170 tons or 2.5 times larger than that without pig damage. This 

substantial increase in sedimentation is expected due to highly sensitivity of the model to the 

surface residue cover parameter as shown in the sensitivity analysis section of this report. 

Nearly half of the surface residue coefficients were decreased to below 60% of their original 

values when pig damage was not accounted for, which translates to an expected increase in 

sediment load. These results highlight the need for a more accurate measurement of the impact 

of pig damage on the residue cover through the watershed. More work is needed to delineate 

the impacted areas and levels of pig damage. The needed work will evaluate the current 

methodology used and suggest adjustment to it based on detailed field measurements. 

Acknowledgements 

This is an executive summary of a project report submitted by the author to the USDANRCS as part the research project funded through them entitled ” Modeling current and 

alternative best management practices on Hanalei watershed using AnnAGNPS.” The author 

would like to acknowledge the following colleagues, Dudley Kubo, Chris Smith, Katina 

Hanson, Dan Moore, Fred Theurer and Mike Robotham from NRCS, Jim Jacobi from USGS, 

Carl Berg from the Hanalei Watershed Hui, Farhat Abbas, Viktor Polyakov and Chui Cheng 

from University of Hawai`i-Manoa.

32
Photographic Time Series of Sedimentation Near the Wall, Hanalei 

Bay, Kaua`i, Summers of 2005 and 2006

Mike Field1, Hank Chezar1, and Curt Storlazzi1

Introduction 

The USGS Coral Imaging System is used to provide visual documentation of 

sedimentation on coral surfaces that can then be correlated with measurements of waves, 

currents, rainfall, and stream discharge. The camera obtains a high-resolution digital still 

image every four hours (4 am, 8 am, noon, 4 pm, 8 pm, midnight) with the time and date 

recorded. Companion instruments record light penetration, or turbidity, and the camera images 

show whether the particles actually settled on the bottom or were transported through the 

region. The camera was deployed in 2005 and again in 2006 on the seafloor offshore of the 

mouth of the Hanalei River and adjacent to the Wall at a depth of about 10 m. A gridded 

concrete block was used as a proxy for an irregular coral surface so that estimates of levels of 

sediment accumulation—and erosion—could be correlated with other measurements and 

improve our understanding of under what conditions sediment affects corals. The over-all goal 

was to observe patterns in sediment accumulation and/or erosion on the seabed and coral 

communities, and relate those observations to synchronous measurements of waves currents, 

turbidity and stream discharge. 

Summer 2005 Results 

The 2005 study showed a slow, steady covering of the flat concrete block by muddy 

sand within the month of June. Throughout the remainder of the summer there was little 

change to the amount of sediment. There were, however, apparent changes in texture, as the 

surface sediment alternately became finer or coarser. The changes on the block surface 

mirrored changes observed in the adjacent bottom sediment, and appeared to reflect mild 

reworking by small waves in addition to burrowing/grazing organisms. This is consistent with 

the low-to-absent wave stresses and very weak currents during the 2005 summer (Storlazzi 

and others, 2006). The patchiness of the sediment layer on the block surface indicates small 

amounts of sediment being removed and infilled over short time periods (one day). Their 

irregularity and randomness indicates that they are more likely caused by feeding patterns of 

invertebrates than by physical forces. 

 

1

 USGS Pacific Science Center, 400 Natural Bridges Dr., Santa Cruz, CA 95060 

33
Summer 2006 Results 

The photographic time series for the summer of 2006, using a new tripod adjustable in 

the vertical, horizontal, rotational and angular planes, showed a more complex pattern than 

2005, largely as a result of the large volumes of sediment injected into the inner bay during the 

floods of February and March, 2006, and smaller amounts during the experiment in early 

August. From the deployment in June 5 until inspection and cleaning on July 10, there was a 

gradual, continuous build-up of sediment on the block surface, with no evidence of sudden 

events (deposition or erosion) caused by waves and currents. Adjacent live corals seem to 

have been unaffected by the mild sedimentation. Between July 19 and July 23 the amount of 

sediment markedly increased, and this period correlates with a period of increased wave 

stresses as recorded at the south-central reef and along the inner Wall. The bottom camera 

captured discharge into the bay following the early August flood of the Hanalei River. 

Flocculated particles first appeared in the water column between 8 pm and midnight on 

August 6. Between 4 am August 7 and 4 am August 8, the suspended sediment concentrations 

were high enough to cause a complete “brown-out.” The water remained turbid for the next 48 

hours, and finally cleared by 4 am on August 10. 

Sediment on the block surface was collected on July 10 and again when the camera 

was recovered in September. Total dry weight of the sediment covering about 30% of the 

block on July 10 was 2.84 g and was 68% terrigenous in composition. The sediment 

accumulation rate over a period of 36 days was 3.5 g/m2

/day. In September, the block was 

recovered, and the sediment on its surface and top edge was retained; it was 85% terrigenous 

in composition and had a weight of 38.27 g. The sediment accumulation rate over a period of 

60 days was 6.0 g/m2/day, or nearly twice as great as the first part of the summer. 

Summary 

The key observation for 2005 and 2006—two years with vastly different discharge 

records—is that sediment covered a block along the base of the Wall within several weeks and 

the sediment remained on the block for the remainder of the summer, except for minor 

changes due to small waves and feeding organisms. This information has strong implications 

for the success of coral recruitment to hard surfaces at this location following the spawning 

that occurs in summer months as the mantling by sediment eliminates a large number of 

potential recruitment surfaces. 

References 

Storlazzi, C.D., Presto, M.K., Logan, J.B., and Field, M.E., 2006, Coastal circulation and 

sediment dynamics in Hanalei Bay, Kaua`i; Part I - Measurements of waves, currents, 

temperature, salinity and turbidity; June-August, 2005: U.S. Geological Survey Open-File 

Report 2006-1085, 35 p. 

34
35
Resistance and Resilience of a Hawaiian Coral Reef Fish Assemblage 

to Dynamic Natural Conditions: Hanalei Bay, Kaua`i - 1993 to 2005

Alan Friedlander1 2and Eric Brown3

Coral reefs in dynamic natural environments with limited human impacts allow us to 

examine how these systems respond to natural disturbance over time. In Hawai`i, a limited 

number of data sets exist to examine the resilience and resistance of coral reef ecosystems to 

disturbance. Hanalei Bay on the north shore of the island of Kaua`i has been monitored since 

1992, providing at unique date set in which to examine changes in the composition of the coral 

reef community during this time. Hanalei Bay is directly exposed to large winter swells with 

high surf, as well as frequent heavy winter rainfall and high river discharge. 

Fish assemblages were assessed at 20 permanently marked locations using standard 

underwater visual belt transect survey methods. A SCUBA diver swam each 25 m x 5 m 

transect at a constant speed and identified to the lowest possible taxon, the numbers and sizes 

of all fishes visible within 2.5 m to either side of the centerline (125 m2

 transect area). 

Transects were sampled monthly between 1992 and 1994 and then once in 1999, 2003, 2004, 

and 2005. 

Reef fishes in Hanalei Bay demonstrated distinct assemblage structures and 

characteristics based on specific hard-bottom habitat types. The highest number of fish species 

was associated with deeper habitats that had high structural complexity. Low numbers of 

species were observed on reef flats that were distant from sand areas and had low habitat 

relief. High biomass was also associated with reef-edge habitats and areas with high habitat 

complexity. Habitats with low spatial relief and limited shelter, particularly when distant from 

reef edges, were associated with low standing stocks for most fish species. 

The higher number of species and biomass at deeper depths is likely the response to 

the impact of large waves on the shallow reefs and the refuge provided by deeper water. 

Fishes were more abundant and diverse nearer the reef edge. The sharp interfaces that edges 

provide between habitats with greatly different physical and biological properties often result 

in higher movement dynamics and abundance of predators, prey, spawners, and migrators. 

Monthly visual fish censuses of transects from December 1992 to November 1994 

showed that surf height and degree of wave exposure were negatively correlated with several 

measures of assemblage organization. Most measures of fish-assemblage structure were lower 

 

1

 NOAA, National Ocean Service, National Centers for Coastal and Ocean Science, 

Biogeography Team 

2

 The Oceanic Institute, 41-202 Kalanianaole Highway, Waimanalo, HI 96795 

3

NPS, Kalaupapa National Historical Park, PO Box 222, Kalaupapa, HI 96742

36
during the winter months when large north Pacific swells and heavy rainfall, coupled with 

high river discharge, impacted the bay. 

Species richness and diversity have remained relatively constant over the 12-year 

survey period. Biomass has, however, increased by 38% during this time period. Three 

introduced species have increased in abundance since 1993 and now account for over 30% of 

the total fish biomass in the bay. Increases in total fish biomass since the early 1990s cannot 

be attributed solely to introduced species, as other elements of the fish assemblage have also 

increased over this time period. Reduced fishing pressure has been cited as one potential 

reason for these trends. 

The entire fish assemblage, based on numerical abundance, has fluctuated over time 

with no apparent trend (fig. 1). Assemblage structure in the low-relief and shallow habitats has 

shown the greater amount of variability while the deep slope and the spur and groove habitats 

appear most stable. These changes are likely responses to environmental variability, and the 

relatively intact condition of the fish assemblage compared with other more exploited 

locations around Hawai`i may provide the resistance and resilience to change necessary under 

harsh and variable environmental conditions. 

c93

c94

c99

c03

c04

c05

d93

d94

d99

d03 d04 d05

f93

f94 f99

f03

f04

f05

s93

s94

s99

s03

s05 s04

sp93

sp94

sp99

sp03 sp04 sp05

Low relief

Complex

backreef

Deep slope

Spur & groove Shallow slope

Figure 1. Multi-dimensional scaling plot of reef fish assemblages over time in five major 

habitats in Hanalei Bay, Kaua`i from 1993 to 2005. 

37
Background References 

Friedlander, A.M. and Brown, E.K., 2005, Hanalei benthic communities since 1992; spatial 

and temporal tends in a dynamic Hawaiian coral reef ecosystem: Hawai`i Cooperative 

Studies Unit, Pacific Aquaculture and Coastal Resources Center, University of Hawai`i at 

Hilo, Hawai`i Cooperative Studies Unit Technical Report HCSU-003, 32 p. 

Friedlander, A.M. and Parrish, J.D., 1998, Temporal dynamics of the fish assemblage on an 

exposed shoreline in Hawai`i: Environmental Biology of Fishes, v. 53, p. 1-18. 

Friedlander, A.M. and Parrish, J.D., 1998, Habitat characteristics affecting fish assemblages 

on a Hawaiian coral reef: Journal of Experimental Marine Biology and Ecology, v. 224, no. 

1, p. 1-30. 

Friedlander, A.M. Parrish, J.D., 1997, Fisheries harvest and standing stock in a Hawaiian Bay: 

Fisheries Research, v. 32, no. 1, p. 33-50. 

Friedlander, A.M., DeFelice, R.C., Parrish, J.D., and Frederick, J.L., 1997, Habitat resources 

and recreational fish populations at Hanalei Bay, Kaua`i: Project report by the Hawai`i 

Cooperative Fishery Research Unit to Hawaii Department of Land and Natural Resources. 

296 p.

38
Developing Tools for Assessing Land Based-Contamination Impacts in 

Corals 

Laetitia Hédouin1 and Ruth Gates1 

Coastal development and changes in land use critically threaten Hawai`i’s coral reefs. 

These practices have lead to the contamination of coastal environments with sediment and 

runoff. This is evident in Hanalei Bay, Kaua`i, where coral reefs have been negatively 

impacted by high sediment loading. The objective of our study is to develop tools for 

assessing the impact of land-based contamination on coral reefs in Hanalei Bay, one of the 

priority watersheds identified by the Land-Based Pollution Local Action Strategy of Hawai`i. 

The goal of this project can only be met by linking the levels of exposure to land based 

contamination with specific biological behavior in corals in Hanalei Bay. To accomplish this, 

a detailed understanding of the exact nature of the stressors found in the watershed is required. 

Therefore, six stations were identified in Hanalei Bay where the species of major interest 

(Montipora capitata, Porites compressa and P. lobata) were present and superficial sediment 

samples were collected at each location for analyses of grain-size, composition and metalloid 

and metal concentrations. Then, the following specific objectives will be addressed in Hanalei 

Bay: 

• Monitor turbidity, temperature and salinity at the six sampling stations and deploy 

sediment traps to measure sediment deposition rates, 

• Define the coral community composition at these sampling sites, 

• Identify gene targets that are sensitive to, and thus indicative of coral exposure to landbased contamination (e.g. sediment, contaminant) using microarray, 

• Characterize histological changes in coral tissues associated with exposure to landbased contamination, and 

• Analyze these data to identify the biological trait or traits that most tightly correlate 

with the levels of land-based contamination exposure in Hanalei Bay. 

This work will characterize the quality and quantity of sediments and a range of cooccurring stressors (e.g. contaminants, temperature, salinity, nutrients) in Hanalei Bay, and 

provide a detailed understanding of how these exposures are reflected in the biology of coral 

across a range of temporal scales. Sediment specific gene expression profiling will be used to 

characterize current exposure states in corals; histological analyses will be informative about 

sediment impacts on corals on a scale of days to weeks, and coral community structure will 

 

1

 Hawai`i Institute of Marine Biology, PO Box 1346, Kaneohe, HI 96744 

39
reflect sediment impacts on a scale of months to years. Using this multi-scale approach we 

will define the causal relationship between sediment stress and changes in coral health and 

identify the most appropriate tool for evaluating these impacts in real time on Hawaiian coral 

reefs. As such, this project will identify and field test a management relevant tool (or suite of 

tools) that has the potential to underpin state-wide monitoring of land-based contamination in 

corals and serve as the rationale for improving land use practices in these areas. 

40
Hydrodynamic Modeling of Hanalei Bay 

Ron Hoeke1 and Curt Storlazzi2

The fates of sediments, nutrients, pathogens, and pollutants introduced to Hanalei Bay 

by the Hanalei River, as well as by other streams and groundwater discharges around the bay, 

are largely unknown. Gaining a spatially explicit understanding of residence times, bed sheer 

stresses, and overall circulation within the bay under varying conditions would greatly aid in 

predicting the trajectories of these materials and the water quality of the bay. In order to 

address these concerns the Delft3D numerical circulation model has been applied to estimate 

the relative contributions of waves, winds, tides, and river floods on the hydrodynamics of the 

bay. This model will draw heavily on USGS field data collected during the summers of 2005 

and 2006 and from instruments currently deployed over the 2006-2007 winter season. In 

addition to providing information about sediment processes and water quality, the model will 

provide insight on larval recruitment and dispersal (are the reefs self-seeding and why has 

coral recruitment been so high?), as well as the distribution of benthic habitats. 

Preliminary results provide insight into the relative contributions of each of the major 

forcings. Episodic NW swell creates flows and bed shear stresses that are orders of magnitude 

greater than modal wave conditions, or the contributions from tide and wind. When the model 

is forced with 3 m, 15 sec NW swell, a condition the bay experiences 30 or more days in an 

average winter season, depth-average residual flows reach 0.6 m/s over the reef flats well 

inside the bay; bed shear stresses are high over most of the bay’s floor; and a well developed 

jet moves water offshore in the center of the bay (fig. 1A). Conversely, when the model is 

forced with more modal, summertime conditions, (1 m, 9 sec, ENE swell and 5 m/s trade 

winds), flows within the bay are less than 0.1 m/s and bed shear stresses in the interior floor of 

the bay are very low (fig. 1B). Modeled bed shear stresses remain very low in the area known 

as the “Black Hole” off the mouth of the Hanalei River through both of the modeled 

conditions. 

Future plans include tuning the model with in situ observations and using components 

of the model in a near-real-time and forecasting mode to provide public health and safety 

bulletins for the bay. 

 

1

 Joint Institute for Marine and Atmospheric Research (JIMAR), University of Hawai`i, 1000 

Pope Rd., Honolulu, HI 96822 

2

 USGS Pacific Science Center, 400 Natural Bridges Dr., Santa Cruz, CA 95060 

41
Figure 1. Modeled depth-averaged current velocities (white arrows) and bed shear stresses at 

Hanalei Bay; A) 5 m/s ENE wind, 3 m, 15 s period, NW swell; B) 5m/s ENE wind, 1 m, 9 s period, 

ENE swell; instrument arrays in both A and B are indicated.

42
Mapping Plant Species and Communities in the Hanalei Watershed 

Jim Jacobi1 and Stephen Ambagis2

The focus of this project was to produce a detailed map depicting the distribution of 

native and alien plant communities and selected invasive species for the Hanalei watershed on 

the island of Kaua`i. This vegetation map will serve as one basis for sampling, analyzing, and 

interpreting other ecological data collected in this area relative to erosion and fine sediment 

transport through the watershed. 

Plant communities within the Hanalei watershed were mapped using spectral analysis 

of digital images. The imagery for this classification was collected by the Quickbird satellite 

on January 5, 2004 and April 28, 2003. These images have four spectral bands plus a 

panchromatic (black and white) band, and spatial resolution (pixel size) of 2.6 meters for the 

multi-spectral data and 0.5 m for the panchromatic band. The analysis was primarily 

conducted using an object-based classification program called eCognition. The advantage of 

using an object-based classification program is that it allows for the incorporation of spectral 

as well as size, shape, and textural components of the data into the analysis. 

To facilitate fieldwork in the watershed, we established a total of 15 sites (Landing 

Zones or LZs) where we could land a helicopter. The 15 LZs served as focal points for 

conducting the plant studies, as well as for many of the other terrestrial components of this 

research program. Most of the LZs were located along the main stream channel, but two of the 

sites were in hanging valleys that included tributaries that fed into the main Hanalei River. 

Plant sampling included establishing ground-truth plots that were used to calibrate the digital 

analysis of plant communities on the satellite imagery, and a set of 38 formal vegetation 

sampling plots to characterize the composition and structure of the mapped plant communities. 

We also collected data on the distribution and intensity of ground disturbance caused by feral 

pigs throughout many parts of the watershed. 

A total of 26 plant communities and species were mapped within the Hanalei 

watershed (fig. 1). Given the extremely high resolution of the satellite imagery, the vegetation 

map displays both community and species units. Most of the native-dominated plant 

communities currently found within the Hanalei watershed are above 2,500 ft elevation, 

particularly on the upper western side of the valley. However, the vast majority of the Hanalei 

watershed is currently dominated by alien species. This is likely due to the rapid invasion of 

this area by several alien plant species, particularly following major damage to the native plant 

communities during hurricanes Iwa and Iniki in 1982 and 1992, respectively. Much of the 

valley floor and the lower slopes above the river are dominated by guava with an understory 

 

1

 USGS Pacific Island Ecosystems Research Center, Kilauea Field Station, Hawai`i National 

Park, HI 96718 

2

 USGS Hawai`i Cooperative Studies Unit, University of Hawai`i at Hilo/PACRC, Kilauea 

Field Station, Hawai`i National Park HI 96718 

43
of Clidemia and Lantana. It also appears that several highly invasive plant species, including 

Albizia, Australian treefern, strawberry guava, Malabar melastome, and rose myrtle, are 

rapidly increasing in both distribution and abundance across the lower part of the watershed. 

Any use of trade, product, or firm names in this presentation is for descriptive purposes 

only and does not imply endorsement by the U.S. Government. 

Figure 1. Plant communities mapped within the Hanalei watershed.

44
Impact of Sediment, Storm Waves and Storm Floods on Hawaiian Reef 

Communities

Paul Jokiel1

Major storms are infrequent events of high intensity and short duration that can exert a 

profound influence the structure of Hawaiian reefs. Extreme wave energy directly damages 

corals and retards coral community development. A paradox is that storm surf also represents 

a positive factor that maintains vitality of many communities through the mobilization and 

removal of terrigenous, calcareous and organic sediments that otherwise will smother a reef 

system. Flood events erode watersheds and deposit sediments on the reefs that can kill corals 

and block recruitment of new coral colonies. Fresh water delivered by storms also can lower 

local salinity to levels that are lethal to corals and other reef organisms. Nutrients and 

pollutants associated with fresh-water runoff are transported onto coral reefs during such 

storms. The impact of these events is poorly understood for several reasons. These events are 

transient in nature and seldom are observed directly on reefs due to difficulties in making 

observations during conditions of extreme wave motion or turbidity. The duration of most 

coral reef investigations is too short to allow evaluation of the major storm events that occur 

with a frequency of decades to hundreds of years. The pattern of impact for a major storm is 

highly complex, and influenced by local bathymetry, shoreline topography and directionality 

of the storm event. Nevertheless, sufficient data are available to provide a general spatial and 

temporal description of the relative importance of major storm waves and storm floods on 

reefs throughout the main Hawaiian Islands. Recent studies at Pila`a reef on the northeast 

coast of Kaua`i provide insight into the dynamic changes brought about by poor land 

management and the subsequent recovery period of the coral reef community. The relative 

impact of wave damage, damage due to terrigenous sediment runoff and damage due to factors 

associated with fresh water are summarized for the major Hawaiian coral reef habitats in 

relation to questions being developed for the ongoing research program at Hanalei Bay. 

 

1 University of Hawai`i, Coral Reef Assessment and Monitoring Program, Hawai`i Institute of 

Marine Biology, PO Box 1346, Kaneohe, HI 96744 

45
Submarine Groundwater Discharge in Hanalei Bay: Impacts on 

Coastal Water Quality

Karen Knee1, Blythe Layton2, Alexandria Boehm2, Joseph Street1, Carl Berg3, and Adina Paytan1 

Submarine groundwater discharge (SGD) represents a potentially important, but poorly 

quantified, source of freshwater, nutrients and pollutants to the coastal ocean. In Hanalei Bay, 

high fecal indicator bacteria (FIB) counts, particularly after heavy rains, raised suspicions that 

sewage was leaching into groundwater and discharging directly into the bay. This study, 

conducted in March 2005 and August 2006, used radium, a natural groundwater tracer, in 

combination with salinity, to characterize groundwater mixing and discharge in this area and 

assessed the importance of groundwater as a source of nutrients and pollution to the surf zone. 

When radium activity was plotted against salinity, a three-endmember mixing system 

consisting of fresh groundwater (low salinity, low radium), saline groundwater (high salinity, 

high radium), and seawater (high salinity, low radium) became apparent. Groundwater 

sampled from temporary wells in the beach face revealed that the coastal aquifer is a dynamic 

zone in which these three endmembers mix. A small, but noticeable, salinity depression 

occurred near shore in areas not located near a stream or river, indicating the discharge of 

freshened groundwater (fig. 1). 

Hanalei Bay, Waioli Site

34.5

34.55

34.6

34.65

34.7

34.75

34.8

34.85

34.9

34.95

Distance from Shore (Ankle to Offshore)

High Tide 8/16

Low Tide 8/16

High Tide 8/19

Low Tide 8/19

Waioli Pit Transect Aug. 2006

0

5

10

15

20

25

30

35

20 15 10 5 0

Distance from high water mark (m)

Figure 1: Example of salinity gradient in groundwater and nearshore, Waioli Beach. 

Concentrations of all nutrients measured (nitrate+nitrite, phosphate, silicate, and 

ammonium) were higher in groundwater than in nearshore water, and concentrations of 

nitrate+nitrite were higher in groundwater than in any other water sampled, including streams 

 

1

 Stanford University, Department of Geological and Environmental Sciences, 450 Serra Mall, 

Braun Hall, Bldg. 320, Stanford, CA 94305-2115 

2

 Stanford University, Department of Civil and Environmental Engineering, Terman 

Engineering Center, M 42, Stanford, CA 94305-4020 

3

 Hanalei Watershed Hui, PO Box 1285, Hanalei, HI 96714 

46
and the Hanalei River (fig. 2). This indicates that groundwater could be an important nutrient 

source to nearshore waters in Hanalei Bay. High variability within sample groups 

(groundwater pits, nearshore, Hanalei River, streams and Hanalei open bay) illustrates that 

these classifications, especially groundwater, represent a complex mixing zone rather than a 

uniform end member. 

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

Hanalei River Streams Pits Nearshore Hanalei Bay

Phosphate (micromolar)

March 2005

August 2007

0

1

2

3

4

5

6

Hanalei River Streams Pits Nearshore Hanalei Bay

N+N (micromolar)

March 2005

0

50

100

150

200

250

300

350

400

Hanalei

River

Streams Pits Nearshore Hanalei Bay

Silicate (micromolar)

March 2005

August 2007

Figure 2: Nutrient concentrations at various site types, Hanalei Bay, March 2005 and August 

2006 

Fecal indicator bacteria (total coliform, E. coli, and Enterococcus) were measured in 

the Hanalei River, streams, groundwater and the nearshore zone. Most samples were below 

the detection limit for these bacteria; however, the bacteria were detected in all samples 

collected at the Queen’s Bath spring in Princeville (fig. 3). The highest levels of all fecal 

indicator bacteria tended to occur in streams; however, the fact that fecal indicator bacteria 

were observed in some groundwater samples merits further investigation. A small subset of 

sites from the August 2006 sampling were screened for the presence of a human-specific 

Enterococcus marker, the esp gene. One hundred percent of the samples screened (n = 4) were 

positive for the marker. This indicates that at least a portion of the bacteria present at these 

sites originated from sewage. The presence of this marker strongly supports the need for 

further study of fecal contamination at Hanalei Bay. 

Future work will focus on calculating SGD-related fluxes of water and nutrients to the 

coastal ocean, investigating the efficacy of caffeine as a wastewater indicator in this area, 

47
assessing the influence of land use on nutrient subsidies from SGD, using Ha`ena, Hanalei, 

and Princeville as comparison sites, and tracking the source of fecal indicator bacteria entering 

the bay using the esp gene. 

0

5

10

15

20

25

30

35

<10 10-99 100-999 >1000

E. coli level

0

10

20

30

40

50

60

<10 10-99 100-999 >1000

Enterococcus level 

Sand 

Queens Bath Spring

Ankle-depth Samples

Pits/Groundwater

Rivers

Streams

Figure 3: Fecal indicator bacteria in the Hanalei Bay area. The x-axis divides samples into 

order of magnitude class, and the y-axis shows the number of individual samples falling into 

each class. 

48
Hanalei Bioassessment Survey 

Linda Koch1

The Hawaii State Department of Health’s methodology of determining ecosystem 

health employs a holistic approach that evaluates the entire watershed as an extended 

ecological unit. Instead of simply evaluating specific points along the stream to determine 

species composition and abundance, we consider multiple lines of evidence to determine the 

health of the entire system. These lines of evidence include the habitat available for various 

species, both native and introduced, riparian zone integrity and composition, erosion evidence, 

bottom types, water chemistry, as well as, information regarding previous studies, water use, 

land use and classification. 

Visits utilizing the Hawai`i Stream Bioassessment Protocol (HSBP) were conducted 

between August 29, 2006 and September 1, 2006 on 4 sites in Hanalei watershed. Two lower 

sites and two upper sites were accessed by helicopter. The assessments were conducted on 

relatively sunny days with a few light rain showers. 

Previous investigations from researchers indicate a significant population of introduced 

species including several predacious species. Results from the assessments indicate that a 

relatively good aquatic community was present in the watershed. Overall species composition 

was favorable, but habitat was somewhat degraded in the lower sites. 

 

1

 Hawaii State Department of Health, Environmental Planning Office, 919 Ala Moana Blvd., 

Rm. 212, Honolulu, HI 96814 

49
USDA Natural Resources Conservation Service Assistance to Hanalei 

Dudley Kubo1

The designation of Hanalei as an American Heritage River by President Clinton, in 

July 1998, directed federal agencies to extend their existing programs to the Hanalei 

community. The NRCS authorized the start of a Cooperative River Basin Study for the 

Hanalei River, which funded NRCS staff and permitted NRCS to cooperate with other 

Federal, State, and local agencies in making investigations and surveys. Through the River 

Basin study and other authorities, NRCS has provided assistance to the community, through 

the Hanalei Watershed Hui, in many forms, including the following: 

• NRCS has assisted with watershed modeling to develop sediment discharge estimates 

from the undeveloped upper watershed areas. In 2003, national technical support was 

obtained for the application of the USDA’s Annualized AGricultural Non-Point Source 

Pollution Model to the Hanalei Watershed. AnnAGNPS is a continuous simulation, 

surface-runoff, pollutant-loading model, which subdivides the watershed into cells of 

homogeneous soil type, land use, land management, and precipitation. The difficulties 

of applying the continental, agricultural watershed model to the tropical island 

watershed were many. Cell processes include precipitation, runoff, soil moisture 

balance, crop condition and management, and soil erosion. In the Hanalei Watershed, 

the areal divergence in rainfall required development of numerous climate datasets to 

account for rainfall variability. Topographic relief in the Hanalei Watershed is extreme 

which complicated application of the Revised Universal Soil Loss Equation for 

sediment yield. Landslides and debris flows in the steep upper watershed areas are 

frequent and are considered to be significant contributors to stream sediment. 

Published analytical and empirical coefficients for soil loss and runoff computations 

are generally unavailable for the soil, vegetation, and land management conditions in 

the Hanalei Watershed. 

• Through a convergence of programs and funding sources which included the HWH, 

EPA, USGS Biological Resources Division, USGS Water Resources Division, 

University of Hawai`i, and NRCS, detailed data for soils, vegetation, erosion factors, 

and hydrology were collected. A refined watershed model with the updated 

information is being implemented. Continued national support for AnnAGNPS 

development has been assured. The model outcomes will be used to develop tailored 

and targeted treatments in the watershed to reduce sediment discharge to the estuary, 

sandy beaches, and coral reefs. 

• NRCS participated with the East Kaua`i Soil and Water Conservation District to fund 

operation of the USGS sediment gage on Hanalei River during the 2006 federal fiscal 

 

1

 USDA Natural Resources Conservation Service, PO Box 50004, Honolulu, HI 96850-0050 

50
year. The sediment gage had operated in 2004 and 2005 with grant funds acquired by 

the Hanalei Watershed Hui. The additional year of sediment discharge data included a 

period of prolonged rainfall, which proved valuable in the calibration of the 

AnnAGNPS watershed model. 

• In 2002, NRCS provided funds for travel and expenses for a UH Department of Urban 

and Regional Planning graduate planning practicum to provide assistance to the 

Hanalei community. The twelve students and their instructor, Dr. Luciano Minerbi, 

researched and analyzed using a planning framework three issues: treatment options 

for wastewater, coexistence of taro lo`i (patches) and endangered waterbirds on the 

USFWS refuge, and compatibility of tourism and environmental quality. The 

Practicum Report now serves as a valuable resource for the community. 

• The NRCS Lihue field office has a long history of providing technical and financial 

assistance directly to Hanalei area agricultural producers, especially through the 2002 

Farm Bill programs. Recent activities include working with taro farmers to design and 

implement new lo`i and replace existing leaking ditch systems and inferior water 

control structures with PVC pipe and new water delivery gates. The Field Office staff 

members have also worked with individuals and groups to enhance and restore wetland 

habitat types for the benefit of endangered waterbirds. 

51
Options for the Disposal of Wastewater Effluent in Hanalei, Hawai`i 

West Marrin1,2

For purposes of this review, wastewater disposal options are limited to secondary- and 

tertiary-treated effluent because the disposal of primary-treated effluent via ocean outfall 

systems, which are utilized elsewhere in Hawai`i, is not anticipated to be practical. The 

advantages of a tertiary-treated wastewater effluent over those of a secondary-treated effluent 

include a reduction in (1) suspended and dissolved solids, (2) soluble nutrients, (3) degradable 

organic carbon (BOD5), and (4) some dissolved metals. Currently, both a conventional 

wastewater treatment facility (perhaps a large packaged plant) and some type of constructed 

wetland are under consideration. Given that the populated sections of Hanalei have been 

classified as a natural wetland, it seems unlikely that a “constructed” wetland system could be 

permitted. In lieu of constructing treatment ponds in native soils, enclosed structures known as 

living machines could be placed into the ground. Living machines reportedly emulate 

processes that occur within constructed wetlands and are able to utilize local plants and 

microorganisms to treat wastewater. 

The most obvious option for wastewater effluent is direct discharge into one or more 

of the surface waters running through the Hanalei watershed. This option would be restricted 

to the Hanalei River due to intermittent flows in the smaller streams; however, the potential 

problems with this option are many and varied (e.g., restrictions on NPDES permitting for a 

“Heritage River” and limitations on effluent disinfection because of the toxicity to aquatic 

organisms). For environmental, political, aesthetic, and countless other reasons, surface water 

discharge does not appear to be a viable option. 

A second option for treated wastewater disposal is groundwater injection, whereby 

treated effluent is introduced into saline (and presumably unusable) waters underlying the 

shallower freshwater lens. Although the USEPA is a decade into the process of banning 

groundwater injection that disposes both hazardous substances and untreated (or slightly 

treated) sewage, one of the few remaining permissible uses is the discharge of secondary or 

tertiary treated wastewater. The EPA refers to these permissible injection wells as Class V 

Sewage Treatment Effluent (STE) wells, which are permitted individually in the state of 

Hawaii for treatment plants that receive only sanitary sewage (i.e., no hazardous wastes). This 

requirement could be met in Hanalei thanks to the absence of industrial facilities connecting to 

the proposed sewer system. However, the public often associates groundwater injection wells 

with unanticipated and undesirable consequences, as was exemplified by two STE wells on 

Maui that were suspected of contributing to increased nitrate levels in nearby surface waters. 

 The third option for the discharge of wastewater effluent from small treatment works 

(either conventional or constructed wetland) is direct land application—preferably on a plot 

 

1

 Water Sciences & Insights, PO Box 272, Hanalei, HI 96714 

2

 Hanalei Watershed Hui, PO Box 1285, Hanalei, HI 96714 

52
located adjacent to the treatment facility. This option usually incurs relatively low construction 

and maintenance costs, and the infiltration of effluent through shallow soils essentially adds a 

polishing step to the treatment process (i.e., filters out suspended solids, adsorbs some metals, 

reduces nutrients via nitrogen and phosphorus uptake by soil microbes). While land 

application is optimal for some geographic regions, there are a number of papers in the 

scientific literature that document the degradation of native soils and biota (both macro and 

micro) on plots used for the land application of wastewater effluent. A further loss of native 

vegetation to opportunistic species, a gradual change in the chemistry and permeability of 

soils, a climate characterized by heavy rainfall events, and a shallow groundwater table could 

render this option a controversial one for Hanalei. 

The final option for the disposal of wastewater effluent is reuse, whereby effluent is 

used to irrigate lawns, golf courses, or (less frequently) food crops. While there are several 

locations in Hanalei town that could be irrigated using treated effluent, the costs of 

constructing a delivery network could be high. Perhaps the effluent network could be laid 

when the sewer laterals are connected to Hanalei households and businesses. The dominant 

use of irrigation water in Hanalei is for cultivating taro; hence, taro fields represent the most 

logical destination for reclaimed effluent. Most studies on the use of reclaimed effluent for 

crop irrigation have focused on conventional growing techniques (i.e., applying water to the 

ground surface and permitting it to infiltrate). Because the dominant method of taro cultivation 

in Hanalei includes flooding the crop (i.e., similar to rice cultivation), human contact with 

irrigation water is extensive. Consequently, there would have to be a major emphasis on 

disinfecting the water via ozone, UV, or a similar technique before it was delivered to farmers. 

On a positive note, the requirement for reducing soluble nutrients and dissolved organic matter 

(constituting the very ingredients of fertilizers that are used on taro) in the effluent might be 

reduced. Whether the effluent was used to flood taro fields or to irrigate landscaped areas, one 

could encounter public resistance if people were uncomfortable with the standards and 

methods of disinfection. 

53
Climate Data Input to Modeling the Hanalei Watershed 

Daniel Moore1

Watershed modeling with the intention of informing water-quality decisions 

always depends on a hierarchy of data needs. On this blue-green water planet no one 

involved with the environment doubts that often the first questions about what drives 

landscape change should be “precisely how much is the precipitation, precisely where, 

and precisely when?” Estimates of sedimentation and routing of nutrients, pesticides, and 

microorganisms, depend on these questions. 

While much progress has been made in data collection and climate monitoring in 

the last decade, most watersheds remain under-observed. Any statistical use of historic 

data depends on sufficient records, those being at least a decade long. Some watersheds, 

Hanalei included, have elevational relief, which throws uncertainty into the geographic 

extent that point measurements may be taken to approximate. 

This abstract summarizes the effort to adequately characterize the spatial 

distribution of climate input to the watershed model AGNPS. While the model requires 

solar radiation, temperature (max, min, and dewpoint), and wind speed, the geographic 

variation of these data types is not as critical as that of the precipitation. The use of 

AGNPS in other watersheds has shown that model calibration using observed streamflow 

and/or sediment data is greatly restricted without adequate spatial distribution of 

observed precipitation. However, the primary intended use of AGNPS is not in matching 

short-term observations, such as for example, single storm events or any given month’s 

sedimentation, but rather to provide a gauge of the longer-term consequences of 

conservation measures, over, say, multiple decades. The measures accomplish this by 

effecting the short-term, obviously, and the model tracks day-to-day effects, but an 

attempt to closely match observed data at this time scale is generally not fruitful. 

Two long-term precipitation and temperature data-collection sites exist in the 

Hanalei vicinity. Mt. Waialeale, at the top of the watershed, elevation 5148 feet, and 

Princeville Ranch, elevation 345, near the outlet provide sufficient data to make reliable 

statistical estimates of the climate at those stations. Regression analysis between the two 

sites for time periods of a day, week, or month, show that there is absolutely no 

relationship for precipitation. Standing in the rain at Princeville Ranch, one could only 

venture a wild guess at what is happening on Mt. Waialeale. NRCS has shepherded an 

important effort, the PRISM project, to analyze a nationwide dataset and provide maps 

and tables of spatial distribution on a monthly and yearly basis. The adequacy of the 

 

1

 NRCS National Water Quality & Quantity Team, 1201 NE Lloyd Blvd., Ste. 1000, 

Portland, OR 97232 

54
PRISM methodology for Kaua`i is questionable. However, the University of Hawai`i has 

done similar work which may be considered at least a step better than the PRISM results 

for Kaua`i. Figure 1 shows isohyets of one month’s average rainfall on the north side of 

Kaua`i, Hanalei in yellow. 

The relatively unique orthographic layout of the Hanalei gives insight into why 

the two precipitation sites might be expected to bear no relationship. Mt. Waialeale is 

such a high and sudden “poke” of land into an atmosphere that, for thousands of miles 

around, has seen nothing but flatness. It effectively causes its own precipitation. The 

Hanalei riverbed slope steepens fairly gradually over the lower 12.5 river miles from sea 

level to 1,200 ft. From that point, the elevation jumps almost 4,000 ft in the remaining 2.5 

river miles. 

An examination of the Univ. of Hawai`i isohyets for each of the twelve months 

shows a similar pattern, with closer contours at the upper end of the basin. For AGNPS, 

then, we can relate zones 9-13, 16, and 17 (fig. 1) to the Waialeale station, and the 

remaining zones to Princeville Ranch. Using the climate generation algorithms of GEM6 

(A USDA Agricultural Research Service tool) one hundred years of statistically valid 

precipitation and temperature data were generated for Mt. Waialeale and Princeville 

Ranch. For better spatial distribution, secondary climate data streams were obtained for 

the 17 zones in figure 1. The daily precipitation amounts at each zonal centroid were 

obtained by proportioning the known station data using each month’s rainfall isohyets. 

Very little can be done in the short term to improve upon this methodology. 

However, data from the recent within-basin precipitation-collection sites installed by the 

Hanalei Hui may be more immediately useful to help determine the adequacy of 

proportioning with the monthly isohyets. Installation of an NRCS climate station (as part 

of the Soil-Climate Analysis Network) would have similar benefit. 

55
Figure 1. Hanalei climate zones in AGNPS.

56
Survey of Chemical Contaminants in the Hanalei River, Kaua`i, 

Hawai`i, 2001 

Carl Orazio1, Thomas May1, Robert Gale1, John Meadows1, William Brumbaugh1, Kathy 

Echols1

, William Steiner2, and Carl Berg3 

The objective of this study was to assess chemical contamination of the Hanalei 

River as a benchmark for future assessments. Agricultural, urban, and tourism-related 

activities are potential sources of contamination of the Hanalei’s watershed. In December 

of 2001, samples were collected from a reach of the river near its mouth at Hanalei Bay 

and from an upstream reach at the Hanalei National Wildlife Refuge. Samples of water, 

fish (Eleotris sandwicensis, the native Hawaiian O`opu akupa), freshwater clam 

(Corbicula fluminea), Samoan crab (Scylla serrata), and streambed sediment were 

collected. The samples were analyzed for common urban and agricultural organic 

contaminants including organochlorine pesticides, polychlorinated biphenyls, and 

polycyclic aromatic hydrocarbons and for sixty elements including toxic elements such as 

copper, zinc, cadmium, tin, mercury, lead, arsenic, and selenium. Organic contaminants 

were solvent-extracted from the samples and enriched for gas chromatographic analysis 

with electron capture or mass spectrometric detection. Samples for element analysis were 

digested and prepared for inductively coupled plasma- spectrometry or quantitative 

atomic absorption spectroscopy. 

Our study found that concentrations of the organic contaminants and toxic 

elements were very low in the Hanalei River samples. No polycyclic aromatic 

hydrocarbons, polychlorinated biphenyls, or pesticides other than dieldrin (found at 1-2 

parts per trillion) were detected in the water. Very low levels of dieldrin, ranging from 1-

5 parts per billion (ppb, wet weight), and chlordane (<0.3 to 2.1 ppb) were detected in 

fish and crabs from the downstream reach: These pesticide residues are likely from past 

use to control formosan subterranean termites. Polychlorinated biphenyls were not 

detected (<50 ppb) in the biota samples. Concentrations of toxic elements in the biota 

were unremarkable. In the sediments, low levels of polycyclic aromatic hydrocarbons (<3 

- 190 ppb) indicative of combustion sources were detected at the downstream reach. No 

pesticides or polychlorinated biphenyls were detected in the sediments, and arsenic, 

selenium, copper, zinc, cadmium, tin, mercury, and lead were low in concentration and 

below thresholds of ecological concern. 

 

1

 USGS Columbia Environmental Research Center, 4200 New Haven Road, Columbia, 

MO 65201 

2

 University of Hawai`i at Hilo, College of Agriculture, Forestry & Natural Resource 

Management, 200 W. Kawili Street, Hilo, HI 96720 

3

 Hanalei Watershed Hui, PO Box 1285, Hanalei, HI 96714 

57
Concentrations of the organic contaminants and toxic elements targeted by this 

study were below probable adverse effects levels set by the US-EPA for aquatic 

organisms. Assessment of other classes of organic chemical contaminants, such as 

chemicals associated with wastewater treatment effluents, chemicals used in right-ofways and golf courses, pharmaceutical and personal care products, and other chemicals of 

emerging concern, would provide additional information for assessing potential impacts 

of contaminants on the Hanalei River. 

A full report, entitled Survey of Chemical Contaminants in the Hanalei River, 

Kaua`i, Hawai`i, 2001, is available online at http://pubs.usgs.gov/sir/2007/5096/. 

58
Soil Sampling for Cesium-137 and Observations of Streambank 

Erosion in the Hanalei River Watershed 

Paul Pedone1

This work was started as an effort to contribute to the AnnAGNPS modeling of 

the Hanalei River Watershed. This model requires input for the various sediment sources 

within a watershed, such as sheet and rill erosion, streambank and channel processes, and 

mass wasting. In an effort to understand the relative contribution from each of these 

sources, an assessment of the above components was attempted. Soil samples were 

collected from 22 sites on various geomorphic surfaces within the Hanalei River 

Watershed and near Koke`e above Waimea Canyon (fig. 1). The concentration of 137Cs in 

the samples can be used to obtain an indication of erosion sources and floodplain 

deposition within the watershed. The four sites near Koke`e were sampled to check 137Cs 

levels at higher elevations and in differing precipitation zones than those within the 

Hanalei Watershed. The highest sampling elevation in the watershed was above a 

waterfall at approximately 3,800 ft. At this location a sample taken from a colluvial 

bench yielded a 137Cs value of 175 Bq/kg. The highest measurement of 137Cs was in a 

sample of a muck soil (histosol) on a terrace (elevation approximately 1,100 ft). This 

sample had 137Cs value of 236 Bq/kg at a depth of 38-52 cm. Measurement of the samples 

for 137Cs content was performed by Dr. Jerry Ritchie, ARS, Beltsville, Maryland. 

Figure 1. Location of sites sampled for Cesium-137. 

 

1

 USDA Natural Resources Conservation Service, 101 SW Main St., Ste. 1300 Portland, 

OR 97204-3211 

59
Additionally, an assessment of streambank erosion along the Hanalei River was 

made primarily by observations of flight videos, as well as by accessing river segments 

by helicopter. A total of six helicopter trips were made by this author into the watershed, 

during which soil samples were collected, streambank erosion observations were made, 

and streambank recession rates were estimated. Additional observations were made of 

mass wasting occurrences on flights into and out of the various landing zones within the 

watershed. In the lower alluvial section of the watershed, segments of the streambanks 

were observed by kayaking or hiking to various locations, and through comparison of 

aerial imagery of different ages to attempt a change analysis. Streambank erosion and 

mass wasting are significant contributors to the overall sediment yield to Hanalei Bay. 

Erosion of streambanks in the alluvial lowland near Hanalei includes geotechnical 

failures and direct attack by streamflow. The avulsion near the USFWS Refuge boundary, 

in particular, has produced fine sediment that is readily transported to the bay. 

Things to do 

• Sampling potential sediment sources—additional sampling is needed to 

characterize the streambank sources of sediment. To draw conclusions on the 

proportion of sediment derived from surface erosion versus channel erosion, 

additional sampling is needed of the bed and bank materials for cesium content. 

Once the various sites are sampled and tested, an analysis can be performed using 

a mixing model such as the one described by Nagel and Ritchie to determine the 

relative contribution by the different sediment sources. 

• Modeling of streambank erosion and channel processes—more data is needed to 

determine streambank recession rates at erosion sites along the mainstem and 

major tributaries. Data collection should include measurement of bed and bank 

materials for their physical properties, erosion resistance, etc. 

• Mass wasting evaluation—mass wasting in the form of debris flows and slumps is 

a relatively common occurrence within the Hanalei River Watershed. Methods to 

predict timing, volume, particle tracking, and delivery of sediment from this 

source via modeling should be evaluated and developed. 

60
Water Quality Regulation in the Hanalei Bay Watershed 

David Penn1, Amy King2, Andrew Parker3, John Craig4, and Sen Bai3

Over the past ten years, water-quality measurements and observations from 

numerous points within the Hanalei watershed indicated actual and potential exceedances 

of State regulatory limits for turbidity, indicator bacteria, and nutrient concentrations in 

the water column. Riding on the coattails of EPA's Watershed Initiative Grant to the 

Hanalei Watershed Hui, the Hui and the State of Hawaii Department of Health (DOH) 

obtained additional support from EPA to have Tetra Tech, Inc. help us determine how to 

cap pollutant loadings (TMDLs) such that these regulatory concentration limits would not 

be exceeded. 

We established two automated stormflow sampling stations (one freshwater, one 

estuarine) in the lower reaches of Hanalei River and obtained sediment and nutrient data 

from storm events on March 9 and March 16, 2006. We used these results and additional 

data from DOH, HWH, and USGS monitoring efforts to evaluate existing water-quality 

conditions, analyze watershed hydrology and pollution dynamics, and model the 

relationships between watershed characteristics, pollutant mass loading, and receiving 

water quality. The analysis included calculations of pollutant load capacities (based on 

regulatory concentration limits) for each stream and estuary, and allocations of these 

capacities to identified pollutant sources. These allocations provide guidance for 

implementing management measures that lead to load reductions. 

The data confirmed exceedances of the regulatory limits throughout the 

watershed, except for freshwater segments of Waikoko Stream (no data) and Waipa and 

Waioli Streams (no bacterial indicator data, no nutrient exceedances). Total phosphorous 

and total nitrogen concentrations were strongly correlated to sediment concentrations. 

Concentrations of all pollutants generally increased from upstream to downstream, more 

obviously for nutrients than for sediment and indicator bacteria, with ammonia showing a 

distinctively steeper concentration gradient than other nutrients. Model results suggest 

that load reductions of 54 to 98% are required to prevent most sediment and nutrient 

exceedances, 21 to 99% for bacterial indicator exceedances. 

 

1

 State of Hawaii Department of Health, Environmental Health Administration, 

Environmental Planning Office, 919 Ala Moana Blvd., Honolulu, HI 96814 2

 Tetra Tech, Inc., 508 West Main Street, Urbana, IL 61801 3

 Tetra Tech, Inc., 10306 Eaton Place, Ste. 340, Fairfax, VA 22030 

4

 Tetra Tech, Inc., 1230 Columbia Street, Ste. 520, San Diego, CA 92101 

61
 

The modeling framework consists of a series of watershed models (based on the 

Loading Simulation Program in C++ [LSPC]) and a receiving water model (based on the 

Environmental Fluids Dynamic Code [EFDC]). The watershed models predict flow and 

pollutant loadings draining to Hanalei Bay, while the receiving water model simulates 

water circulation and pollutant transport in the estuary/bay system. 

LSPC model output also partitions pollutant loading among land cover types. 

Initial results suggest that the main pollutant sources are open areas (scrub/shrub and 

evergreen forest land cover types), runoff from agriculture, and waterbird impoundments. 

Among these, the bulk of the bacterial source areas appear to include wildlands and 

wetlands in the larger watersheds (Hanalei, Waioli, Waipa) and cultivated lands in 

Waikoko. Management strategies that address TSS are likely to also reduce total N and 

62
total P, and the main source areas for sediment appear to be unmanaged lands in the 

larger watersheds. Cultivated lands in Waikoko are suggested as a major contributor of 

total N and total P, and cultivated lands throughout the watershed seem to represent the 

main source of ammonia and nitrate nitrogen. 

Relative Loadings by Land Cover for the Hanalei Bay Watershed 

Percent of total load 

Land cover 

Percent of total 

area Enterococcus TSS Ammonia NOx Total N Total P 

Bare Land 0.1% 0.01% 0.1% 0.02% 0.04% 0.04% 0.05%

Cultivated Land 2.6% 2% 2% 64% 20% 6% 8%

Evergreen Forest 25.2% 27% 16% 6% 14% 17% 17%

Grassland 3.5% 0.4% 2% 1% 2% 1% 2%

High Intensity

Developed 

0.02% 0.1% 0.1% 0.01% 0.1% 0.003% 0.003%

Low Intensity

Developed 

0.8% 0.4% 1% 0.2% 1% 0.2% 0.2%

Palustrine Emergent 0.6% 7% 2% 4% 7% 3% 2%

Palustrine 

Forest/Scrub 

1.7% 0.3% 2% 1% 1% 2% 2%

Scrub/Shrub 64.5% 63% 75% 24% 55% 70% 69%

Water 0.9% 0% 0.2% 0.1% 0.3% 0.3% 0.4%

The watershed and receiving water models provide a framework for quantifying 

sediment, bacteria, and nutrient loads spatially and temporally throughout the watershed. 

They can be used to identify source “hot spots,” evaluate the relative impact of surface 

and groundwater contributions, and identify monitoring data gaps. Additionally, “whatif” scenarios may be represented within the framework to predict the impact of water 

pollution controls on water quality conditions throughout the stream systems. 

Spatial and temporal variability of water quality remains poorly defined for many 

combinations of flow regime, location, and pollutant. In addition to actively 

implementing watershed load reductions, future DOH interests include: 

1. establishing TMDLs and load allocations for the marine waters (Hanalei 

embayment and open coastal waters) and 

2. developing and executing a comprehensive Hanalei Bay Watershed water 

quality monitoring strategy that provides the information needed to 

improve our understanding of water quality dynamics and to support DOH 

decisions about: 

a. public safety and health (recreational activities and subsistence 

fishing) 

b. attainment of designated uses and water-quality criteria (waterbody 

assessment), and 

c. assigning management priorities and selecting management 

measures (polluted runoff control) 

 

63
Magnetic Study of Sediment in Hanalei Bay and the Hanalei River 

Watershed: Contribution to Understanding Sources and Transport of 

Terrigenous Sediment 

Richard Reynolds1, Michael Bothner2, Carl Berg3, Amy Draut4, and Harland Goldstein1

Investigations of magnetic properties of sediments in the reef-watershed system of the 

Hanalei Bay and Hanalei River, Kaua`i, Hawai`i, complement studies of composition, texture, 

and radioisotopes (7

Be and 137Cs) to determine patterns of sedimentation in the Bay (Draut and 

others, 2006; and this vol., p. 22). These combined studies also provide information about (a) 

sources of sediment; (b) aspects of sediment transport and deposition in the bay-watershed 

system, such as mineral sorting; and perhaps (c) stability of land surfaces that yield flood 

sediment. Samples have been selected from cores, sediment traps, bottom and suspended river 

sediment, and upland sites. The upland sites represent several different landscape settings, 

including taro fields, steep banks of the Hanalei River, mud in minor drainages, poorly drained 

forest floor, and flood sediment that was trapped by a grassy surface between the edge of the 

river and taro fields. 

Magnetic iron oxide minerals in the bay sediments originate in the watershed. 

Magnetic properties of bay sediments record detrital input from the watershed and may reflect 

sources and landscape settings of upland sediment. Magnetic mineral types and magnetic grain 

sizes (domain states) vary among different volcanic rocks according to magmatic composition 

and cooling history (Reynolds and others, 1990; Rosenbaum and others, 1991; 1994), 

variations that are commonly inherited in derived soils and volcanogenic sediments. 

Subsequent changes in magnetic properties result from weathering of soil and sediment (e.g., 

oxidation of magnetite to hematite; development of pedogenic Fe oxides) depending on 

geomorphic, hydrologic, and microbial setting. 

In the cores, magnetite abundance, as determined by magnetic susceptibility and 

isothermal remanent magnetization (IRM), is negatively correlated with carbonate abundance. 

Magnetite abundance thus provides a measure of input of terrigenous sediment to the Bay. 

Moreover, magnetic grain-size parameters reflect bulk-sediment particle size, with increasing 

content of single-domain magnetite correlating with increasing content of fines (silt and clay). 

 

1

 USGS, PO Box 25046, Denver Federal Center, MS 980, Denver CO 80225 

2

 USGS Woods Hole Science Center, 384 Woods Hole Road, Woods Hole, MA 02543 

3

 Hanalei Watershed Hui, PO Box 1285, Hanalei, HI 96714 

4

 USGS Pacific Science Center, 400 Natural Bridges Dr., Santa Cruz, CA 95060 

64
Broad variations in concentration-independent properties (magnetic grain size; relative 

magnetite-hematite abundance) with depth in bay sediments at sites A, C, and I (early and late 

summer, 2006) indicate many sources of upland sediment. Nevertheless, flood deposits 

(defined here as having IRM>0.08 Am2

 kg-1) show much less variation in these properties 

compared with non-flood deposits and with the sampled upland deposits. This observation 

implies (1) an upland source or sources for the flood deposits of winter and summer 2006 

from one or a few distinct landscape settings, or (2) strong mineral sorting of sediment from 

multiple sources during transport in floodwaters that produced nearly uniform iron-oxide 

content in sediment deposited in and near the Black Hole. 

We found no exact match among magnetic properties when comparing flood deposits 

in cores with upland samples. In these comparisons, closest similarities are found with 

sediment in taro fields (five samples) and in banks of the lower river (two samples). Mineral 

sorting during transport in the lower reaches of the river during floods might explain the 

observed small discrepancies in magnetic grain-size parameters, assuming that our samples 

are representative of these landscape settings. 

The magnetic properties of flood deposits in the cores and in sediment trapped near the 

river mouth are closely similar in absolute abundance of magnetite and hematite, in relative 

amounts of these minerals, and in magnetic grain size. Suspended sediment in the river (one 

sample) also yields closely similar results. Sediments in other traps deployed in the bay 

contain lower amounts of magnetite and hematite perhaps caused by sorting out of these highdensity minerals with distance from the river mouth. 

Flood deposits in the cores (again, on the basis of IRM>0.08 Am2

 kg-1) have much 

higher content of 137Cs than non-flood samples. This observation indicates that recent floods 

have tapped, to strong extent, sediment that was exposed to the atmosphere at some point 

about 40-60 years ago. The linkage between high 137Cs and flood deposits appears to be 

controlled by particle size: 137Cs is relatively abundant in fine-grained core sediment, as it 

appears to be also in fine-grained watershed deposits, such as taro fields and flood sediment 

derived from the fields. Similar relations are found for 7

Be in these deposits. Dilution of the 

isotopic signals by high carbonate abundance should also be considered as an explanation for 

this linkage. 

Taken together, magnetic and isotopic data strongly suggest that a significant 

component of recent flood deposits in the Bay have been derived from exposures in the lower 

watershed, much of it possibly from taro fields. Significant contribution from riverbanks 

seems precluded by 137Cs data. We have not obtained samples to evaluate directly any possible 

contributions from intermediate and high elevations (>300 m) that would include landslide 

debris and large areas disturbed by feral pigs. 

65
Background References 

Draut, A.E., Field, M.E., Bothner, M.E., Logan, J.B., Casso, M.A., Baldwin, S.M., Reynolds, 

R.L., and Storlazzi, C.D., 2006, Seasonal flood deposits in Hanalei Bay, Kaua`i, Hawai`i; 

Implications of fluvial sedimentation for coral-reef ecosystems: EOS, Transactions of the 

American Geophysical Union, 87(52), Fall Meeting Supplement, Abstract OS23A-1616. 

Reynolds, R.L., Rosenbaum, J.G., Hudson, M.R., and Fishman, N.S., 1990, Rock magnetism, 

the distribution of magnetic minerals in the Earth's crust, and aeromagnetic anomalies; in

Hanna, W.F., ed., Proceedings of a Workshop in Geologic Applications of Modern 

Aeromagnetic Surveys: U.S. Geological Survey Bulletin 1924, p. 24-45. 

Rosenbaum, J.G., Reynolds, R.L., and Schlinger, C.M., 1991, Effects of cooling on oxide 

mineralogy and magnetic properties near margins of volcanic bodies: EOS, American 

Geophysical Union Transactions, v. 72, p. 138. 

Rosenbaum, J.G., Reynolds, R.L., and Hildenbrand, T., 1994, Insight into the structure of the 

East Rift Zone of Kilauea, Hawai`i, from a rock magnetic study of drill core: VIIth 

International Drilling Symposium Proceedings, p. 142-145. 

66
Figure 1. Magnetic properties of sediment from cores, traps, river (sediment in suspension), 

and upland sites. Plot of isothermal remanent magnetization (IRM, a measure of magnetite 

abundance) vs. the ratio of anhysteretic remanent magnetization to magnetic susceptibility 

(ARM/MS, a measure of magnetic grain size, with higher ARM/MS indicating smaller magnetic 

grain size having relatively more single-domain magnetite). Symbols are as follows: crosses 

are core samples; circles are samples from upland sites; inverted triangles are sediment from 

traps in the bay near the mouth of the Hanalei River; diamonds and hexagon are sediment from 

other traps in the bay; x is the average of all trap sediments; red triangle is the suspended 

sediment. Flood deposits in the bay are defined here as core sediment with IRM>0.08 Am2 kg-1

and are shown in red crosses to the right of the vertical dashed line. Colors of the upland sites 

(circles): dark blue, taro fields; yellow, grassy surface near the fields; olive, forest floor; light 

blue, river banks and river mud near the USGS gauging station on the Hanalei River; purple, 

banks of the lower river; gray, mud and soil from nearby sites along the power-line road at 

about 300-m elevation, east of the Hanalei River. 

67
Figure 2. Magnetic grain size and 137cesium values for sediment from cores and upland sites. 

Plot of 137cesium the ratio of anhysteretic remanent magnetization to magnetic susceptibility 

(ARM/MS, a measure of magnetic grain size, with higher ARM/MS indicating smaller magnetic 

grain size having relatively more single-domain magnetite). Symbols as above. 

68
Geomorphic Assessment of the Hanalei Stream Network Including Preliminary 

Hydraulic Geometry Analysis Results 

Matt Rosener1

The Hanalei Watershed Study was initiated to identify patterns of erosion and sedimentation 

within the Hanalei River Basin and to develop recommendations for management practices to regulate 

sediment yields from the Hanalei Bay watersheds. An investigation into the fluvial processes in the 

Hanalei stream systems is being performed to support the watershed study, focusing on these processes as 

they relate to erosion, transport, and deposition of sediments in the stream channel network. 

Stream channels within the valley range from ephemeral headwater streams generally located near 

the watershed divide, to short first- and second-order tributary streams that connect the headwater reaches 

to the valley bottom, to the fourth-order mainstem Hanalei River channel that ultimately drains through a 

3.5-mile estuary reach to Hanalei Bay. Stream-channel morphology is strongly influenced here by valley 

form, channel gradient, and sediment size (or the presence of bedrock). In parts of the Hanalei Valley, 

particularly along the lower reaches of the mainstem river, riparian vegetation (i.e. hau) is also a 

significant control on channel form. 

Stream channels are generally confined by steep-sided, V-shaped valley sections throughout much 

of the watershed, except the lower valley where the mainstem river breaks out of the confined canyon into 

a broad floodplain. Bed sediments in much of the drainage network are dominated by the cobble – boulder 

size fractions. Field observations suggest that relatively little deposition of fine sediment occurs in the 

steep channel reaches that constitute 

much of the drainage network, although 

the channel bed may act as a significant 

reservoir for fines. Because the 

streambeds are generally heavily 

armored by cobble to boulder-sized 

rock, it is likely that this reservoir is 

only tapped during episodic, peak flow 

events. The riverbed in the lower valley 

grades to gravel, sand, and eventually 

silt/clay substrate, fitting the classic 

pattern of downstream fining. Channel 

gradients span the full range from level 

(along the entire 3.5-mile estuary 

reach) to vertical (for ephemeral 

streams on the val

Hanalei River Bed Profile

0

500

1000

1500

2000

2500

3000

3500

4000

4500

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

River Mile, distance from mouth (miles)

Elevation (feet above MSL)

0

5

10

15

20

Average Channel Gradient(%)

Hanalei River Bed Profile

Average Channel Gradient

Ka'apahu Str. 

junction

Kaiwa Str. 

junction

Ka'apoko Str. 

junction

Waipuna'ae Str. 

junction

Abandoned 

diversion dam

Pekoa Str. 

junction

USGS Gaging 

Station Deposition Reach Transition Reach Erosion & Transport Reach ley walls). 

 1

 Hanalei Watershed Hui, PO Box 1285, Hanalei, HI 96714 

69
During several fly-in field expeditions in various parts of the Hanalei Valley, stream surveys were 

performed to collect information about channel geometry, bed slope, bed/bank stability, and roughness 

elements (both vegetation and bedforms). These factors are all known to significantly affect local channel 

hydraulics and sediment transport capacity. An attempt was made to establish hydraulic-geometry 

relationships for the stream network, using drainage area as a surrogate for bankfull discharge. For this 

analysis a total of 25 cross-section surveys have been performed to date, 7 of these along the mainstem 

Hanalei River and the other 18 on tributary streams, generally just upstream of their confluence with the 

mainstem. Discharge measurements were made at many of the survey sites and these were used to backcalculate hydraulic roughness values for channel segments. These data may be used for routing routines in 

hydrologic models to simulate water and sediment movement through the stream network. 

The results of the hydraulic geometry analysis generally indicate a strong correlation (R2

=0.91) 

between channel bankfull width and contributing drainage area and a weak correlation (R2

=0.40) between 

bankfull depth and drainage area for both the mainstem river and the tributary streams. This result was 

expected due to the dominance of step-pool channel form in a large percentage of the drainage network. 

Step-pool morphology is common in steeper streams 

with large roughness elements such as boulders or 

large woody debris. It is characterized by an irregular 

bed profile broken by frequent steps or sudden 

vertical drops. Much stream energy is dissipated at 

these drops due to the inevitable turbulence that 

develops in these channel reaches. It may be the case 

that strong relationships between bankfull depth and 

discharge (or drainage area) could be developed for 

lower-gradient stream reaches where pool-riffle 

morphology is more dominant (as opposed to step-pool morphology), but the data collected for this 

analysis were not sufficient to test this hypothesis. 

Hanalei Valley - Bankfull Width vs Drainage Area

R2 = 0.9051

1.0

10.0

100.0

1000.0

10.00 100.00 1000.00 10000.00 100000.00

Drainage Area (acres)

Hanalei Valley - Bankfull Depth vs Drainage Area

R2 = 0.3952

1.00

10.00

10.00 100.00 1000.00 10000.00 100000.00

Drainage Area (acres)

Bankfull Depth (feet)

Also of note is the presence of multiple terraces, or abandoned floodplain surfaces, along much of 

the mainstem Hanalei River. These terraces are found consistently at 

heights of 10-25 feet above the present stream grade, providing 

evidence of significant stream downcutting in the past. While channel 

incision is not considered to be a significant erosion mechanism in the 

valley at the present time when compared to hillslope erosion (sheet an

rill, gully, mass wasting) or streambank erosion, it should be noted

this mechanism has been responsible for the evacuation of large 

volumes of sediment from the valley in the past. No data is currently 

available to attempt to date these past periods of major chann

d 

 that 

el incision. 

70
Applying the Science: Taking Steps to Improve Water Quality and Coral Reef 

Communities 

Audrey Shileikis1, Wendy Wiltse1, Hudson Slay2, Dave Penn2, and Katherine Chaston3

The Hanalei Watershed Hui and its many partners have invested significant time and resources to 

understand the dynamics and the impact of pollutants on the coral reefs, estuary, and streams from the 

ridges to the reef. This workshop is a great opportunity to share what we have learned and to identify what 

we need to do next towards achieving our mutual goal to improve water quality and coral reef ecosystem 

function and health in the Hanalei Bay Watershed. 

The U.S. Environmental Protection Agency, the Hawaii Department of Health, and other partner 

agencies represented on Hawai`i’s Local Action Strategy (LAS) to Address Land-Based Pollution Threats 

to Coral Reefs have a strong interest in taking specific steps that will address land-based sources of 

pollution to improve water quality and the health of the coral reef ecosystem. EPA and DOH are working 

to focus appropriate financial, programmatic, and technical resources on a limited number of watersheds 

in the interest of achieving and documenting water quality improvements. 

The Hanalei Watershed Hui and its partners have been working since the late 1990’s to better 

understand and address numerous issues affecting the health and the people of the watershed. The Hanalei 

Watershed was designated as an American Heritage River in 1998, named a priority watershed for the 

Land-Based Pollution LAS in 2003, and received a targeted Watershed Grant from EPA in 2005. Many 

other federal, state, local and non-profit groups, as well as the community have invested significantly in 

the watershed. With the draft total maximum daily load (TMDL) for Hanalei out for public review and the 

2-day Hanalei Watershed workshop providing a forum to exchange information concerning the 

monitoring, assessment, and implementation activities it is a critical time to consider and evaluate 

management options for improving water quality. How will this information be used to support decisions 

intended to improve water quality? Which management practices should be implemented and where? 

What additional assessments are necessary? 

The TMDL Implementation Matrix (below) provides a summary of pollutants and waterbodies, 

potential sources, locations, recommendations and potential implementers, based on the draft TMDL. 

Primary pollutants of concern include nutrient, pathogens, and sediment levels that have affected water 

quality, coral reefs, and the natural ecosystem. Waters in the Hanalei Bay watershed are impaired and on 

the States’ Section 303(d) of Impaired Waters for Enterococcus (fecal indicator bacteria) and turbidity. 

 

1

 U.S. Environmental Protection Agency, PO Box 50003, Honolulu, HI 96850 

2

 State of Hawaii, Department of Health, Environmental Health Administration, Environmental Planning 

Office, 919 Ala Moana Blvd., Honolulu, HI 96814 

3

 Hawai`i’s Local Action Strategy to Address Land-Based Pollution Threats to Coral Reefs, University of 

Hawai`i at Manoa, Dept. of Natural Resources and Environmental Management, 1910 East-West Rd., 

Honolulu, HI 96822 

71
There is also data indicating that the level of nutrients may not meet water quality standards, but the 

waters are not currently on the Section 303(d) list. The draft TMDL calls for a 90-99 % reduction in 

current loads of sediment, Enterococcus, and nutrients.

Goal: To improve water quality and coral reef ecosystem function and health in the Hanalei Bay 

Watershed by 2012. 

Expected Outcomes for the Hanalei watershed: 

• Reduction of pollutant loads and improvement in baseline water quality (as established in 2002) by 

2012 

• Partial restoration of water quality, defined by a delisting of one pollutant in at least one waterbody 

in the watershed by 2012

What is it going to take to reduce pollutant loads and achieve water quality improvements? 

• Where in the watershed (or on what sources) should we focus management efforts? 

• Which management practices have worked and not worked in reducing loads? 

• How do we assess effectiveness of management practices? 

• How much implementation is needed to see results? 

• What kind of support is needed from the LAS, agencies and scientists to sustain the overall 

Hanalei watershed effort? 

72
Example – TMDL Implementation Matrix 

POLLUTANT and Waterbody POTENTIAL SOURCE LOCATION POTENTIAL MGMT ACTIVITIES POTENTIATURBIDITY (SEDIMENT) Hanalei Stream/Estuary; Waioli, Waipa, Waikoko Estuaries 

Alteration of forested landscape by feral livestock, alien tree and plant species Streambank erosion Landslides Cultivated land/taro lo`i 

Forested portions of watershed 

Fishpond/stream restoration Trail restoration/road management Sedimentation basins Determine natural vs. anthropogenic sediment contributions 

Kaua`i Cou(DOFAW), DOH, taro fKamehame

ENTEROCOCCUS Hanalei Estuary 

Individual wastewater systems Feral and domestic animals Soil background 

Wildlands and wetlands in the larger watersheds (Hanalei, Waioli, Waipa) and cultivated lands in Waikoko 

Cesspool closure/upgrade Septic system installation/upgrade Centralized wastewater treatment system Ungulate fencing/management 

Kaua`i Coun

(DOFAW), DOH, taro fKamehame

NUTRIENTS Hanalei, Waioli, Waipa, Waikoko stream/estuary 

Individual wastewater systems Agriculture (fertilizers) Residential use of fertilizer? Pet waste? Watershed background 

Cultivated lands Cesspool closure/upgrade 

Septic system installation/upgrade Centralized wastewater treatment system Education (pet waste, residential fertilizer, etc) 

Sediment management 

Kaua`i Cou(DOFAW), DOH, taro fKamehame

73
Summary of the 2006 Update to the Soil Survey for Hanalei Watershed 

Chris Smith1 and Katina Hanson1 

Soil Mapping 

The focus of this study was to assess soil-mapping deficiencies and provide greater soil 

survey details for the adaptation of the AnnAGNPS Model in Hawaiian watersheds. The most 

recent published soil survey of the island of Kaua`i (Foote, et al 1972) was generally mapped 

at “High and Medium Intensity” for cultivated agricultural lands, lower intensity for grazing 

lands and “Reconnaissance” levels for mountainous terrain. Later efforts (1970s - 1990s) 

populated the soils database with estimated soil properties. This 2006 study included field 

visits to many locations, described the steep mountainous lands in greater detail and assigned 

soil properties, including RUSLE K factors, T factors and hydrologic soil groups (HSG) to 

improve output accuracy of the AnnAgNPS model. 

Generally, the original mapping was accurate in the valley bottoms, lower watershed 

hills, and on the peneplain remnant known as “power line road”. The current effort has shown 

that much of what was mapped as Rough Broken Land (rRR) and Rough Mountainous Land 

(rRT) can be defined into distinct soil series and that each map unit contains more than one 

major component. The drawing below provides a cross-sectional representation of the changes 

to the soil mapping. 

By defining the midslope areas to a greater degree, assessment of erosion source 

potential as well as potential for productivity and reforestation will be improved. Nearly all of 

the steeplands in Hawai`i can be mapped in greater detail than was done in the original 

surveys. This study can serve as a pilot project for future mapping in this humid steep setting 

and similar settings on other islands. 

 

1

 USDA Natural Resources Conservation Service, PO Box 50004, Honolulu, HI 96850-0050 

74
Hihimanu 

Soil Series

Kauka`opuaKauka`opuaiki* Soil 

Complex 

Rock Outcrop-Lithic 

Udorthents 

Soils 

* Tentative Classifications 

Groundwater 

Flowing 

between 

basalt layers

Lepopohaku* 

Soil Series Saprolite 

Terric 

Haplosaprist 

Soils 

Hanalei Soil 

Series 

Hanalei River

Colluvial 

 Toe Slope

Lower & 

Middle 

Backslope Upper 

Backslope 

Head Scarp

(Valley Wall) Stream 

Floodplain Terrace 

Figure 1. Conceptual cross-section drawing of Hanalei Watershed soils. Notes: Ko`olau soils 

not shown but found along Powerline Road and in the Waialeale area; Kauka`opuaKauka`opuaiki Soil Complex mainly on secondary ridges and backslopes not receiving 

colluvium. 

Pig Damage and Landslides 

Much has been learned about effects of pigs and landslides in these areas albeit in a 

semi-quantitative way. It is the consensus of the field study group that severe control of the 

pig population is the one key undertaking needed in order to restore watershed health. 

A few examples of narrow shoot-debris landslides of varying length (3 to 10 meters 

wide) were observed. They appeared to be a combination of live uluhe fern, undecomposed to 

decomposed uluhe litter and a thin soil and saprolite component associated with the uluhe 

rooting zone (estimated from 5 to 25 cm). Revegetation of the slides appears to be visibly 

noticeable within six months and, after one year, the slide scar is almost completely 

revegetated although careful observation in the field or under stereo detect the scar. 

Pig damage by trails or rooting is greatest in steep upland soils, averaging about 50% 

of the surface area. The percentage seems to be less in the lower watershed but few 

75
observations were made there. Among other effects of pig activity, ground cover is removed 

exposing the soil surface to splash detachment of soil particles and microaggregates. This 

process increases the RUSLE K factor and changes the Hydrologic soil group approximately 

two groups (such as B to D). The lack of aeration and ponding of water also creates reducing 

conditions, which is exacerbated by manure additions, rendering the site optimal for anaerobic 

microbe proliferation. The trails are compacted but appear to be less anaerobic and serve as a 

lacework of channels for overland flow.

76
In Situ Measurements of Coastal Circulation and Sediment Dynamics in 

Hanalei Bay, Kaua`i 

Curt Storlazzi1, Kathy Presto1, Josh Logan1, and Mike Field1

Oceanographic measurements were made in Hanalei Bay, Kaua`i, by the U.S. Geological 

Survey (USGS) Coastal and Marine Geology Program’s Coral Reef Project during the summers 

of 2005 and 2006. The studies were designed to better understand coastal circulation and 

particulate dynamics in the bay during summer flood events. A larger goal was to better 

understand the transport mechanisms of sediment, larvae, pollutants and other particles in an 

embayment that hosts a nearshore coral reef ecosystem adjacent to a major river drainage. A 

series of bottom-mounted instrument packages were deployed in water depths of 10 m or less to 

collect long-term, high-resolution measurements of waves, currents, water levels, temperature, 

salinity and turbidity (fig. 1). These data were supplemented with a series of vertical instrument 

casts to characterize the vertical and spatial variability in water-column properties within the bay. 

The water in Hanalei Bay is generally more saline and cooler farther offshore and with 

increasing depth (fig. 2). These general trends, however, are greatly influenced by the presence 

of freshwater either from river/stream discharge or groundwater effluence; lower salinities and 

higher turbidities were observed closer to shore, especially near the mouths of the Hanalei River 

and the Waipa and Waioli Streams. Flow was relatively weak and circulation was sluggish in 

Hanalei Bay during both summer study periods. Currents were generally oriented parallel to 

shore but varied vertically: the direction of near-surface flows was often the opposite to that of 

near-bed flows, causing vertical velocity shear. Net near-surface flow was into the eastern 

portion of the bay and out of the western portion of the bay; net near-bed flows had an opposite 

pattern. Most of the daily variability in current speed and direction at the study sites is due to the 

influence of tides. As the tide rises (floods), tidal currents close to the surface along the “Wall” 

off the Hanalei River’s mouth flow to the southeast and are greater than those observed when the 

tide falls (ebbs) and tidal currents are to the northwest. The flow close to the seafloor at this 

location appears to be in the opposite direction. The near-surface currents caused by the flood 

tide at the western side of the bay at the CRAMP site flow to the southeast; current speeds are 

slower than those observed when the tide falls and tidal currents are to the northwest. Nearbottom flow at this location also appears to be in the opposite direction. Overall, the tidal 

currents were faster but less consistent in the alongshore direction at the CRAMP site than along 

the Wall. The waves were relatively small during both summers and primarily driven by the 

northeast trade winds. Both waves and currents, and the resulting seabed shear stresses, were 

more energetic in the western and southern portions of the bay that are more exposed to the trade 

winds, resulting in little to no fine-grained sediment accumulation in these areas. More than 90% 

of the time the wave- and current-induced seabed shear stresses along the Wall during both 

summer deployments were so low that the fine-grained terrestrial sediment discharged from the 

 

1

 USGS Pacific Science Center, 400 Natural Bridges Dr., Santa Cruz, CA 95060 

77
Hanalei River during the previous winters’ floods and small summer floods was not able to be 

mobilized and thus was not transported out of the bay. 

Figure 1. Location and description of the instrument packages employed in the 2006 study. The 

numbers following the parameters denote the depths of the measurements below the sea surface 

in meters. CRAMP refers to the University of Hawai`i Coral Reef Assessment And Monitoring 

Program. 

78
Figure 2. Spatial variability in surface water column properties in June 2006. 

79
Streamflow and Suspended Sediment Load in the Hanalei River 

Gordon Tribble1 and Barry Hill1

Streamflow from the upper 18.7 square miles of the Hanalei watershed was measured at a 

gage operated by the USGS (Station 16103000) during the period 1912-1919, and since 1963. 

For the period of record, the median daily flow has been 127 cubic feet per second (cfs), and the 

lowest recorded daily flow was 31 cfs during several days in 1975. The highest recorded daily 

flow, 7,100 cfs, occurred on Nov. 9, 1995. The highest instantaneous peak flow, 44,600 cfs, 

occurred on Nov. 3, 1995. Annual peak flows between 1963 and 2006 have averaged 16,310 cfs. 

Between 1926 and 1993, water was diverted upstream of the gage into the Hanalei Tunnel 

System, which transported an average of 36 cfs out of the watershed. Since 1993, the median 

daily flow at the Hanalei River gage has been 133 cfs. 

To determine the daily load of suspended sediment, understand patterns of sedimentation, 

and provide data for the calculation of numerical models, the USGS operated an automated 

sampler at the Hanalei River gage from October 1, 2003 to September 30, 2006. Sediment 

samplers were collected at regular timed intervals and more frequently during periods of high 

flow. 

For the three-year period of operation, the total computed load of suspended sediment 

was 78,061 tons. The median daily load was 2.1 tons, whereas the highest daily load was 14,003 

tons (Feb. 21, 2006). Sediment loading was very episodic. Half of the total load occurred during 

6 days (out of 1,096) from different storms. Two-thirds of the total load occurred during 13 days 

during the three-year measurement period; each of those days had a suspended sediment load of 

more than 1,000 tons. The cumulative load as a function of time is shown in the figure below. 

The movement of sediment is driven by rain that subsequently enters the Hanalei River. 

Of the 13 days with the highest sediment load, 11 were among the 13 with the highest daily 

streamflow. For the 73 days that contributed 90% of the cumulative load during the 3-year 

period, the correlation coefficient between daily streamflow and daily load was 0.81. 

Rainfall data the site of the stream gage (USGS Station 221101159280801) and at the 

summit of Mt. Waialeale (the top of the Hanalei watershed, USGS Station 220427159300201) 

are poorly correlated with the suspended sediment load. For the 73 days that contributed 90% of 

the cumulative load during the 3-year period, the correlation coefficient between rainfall at the 

Hanalei rain gage and daily load was 0.52. For the same days, the correlation coefficient between 

rainfall at the Waialeale rain gage and daily load was 0.44. To develop an effective numerical 

relation between sediment load and both rainfall and streamflow, it is probably necessary to use a 

watershed model that simulates the mechanisms of erosion and sediment transport in the Hanalei 

watershed. 

 

1

 USGS Pacific Islands Water Science Center, 677 Ala Moana Blvd., Ste. 415, Honolulu, HI 

96813

80
The record of sediment load is based on 912 water samples collected during the threeyear period. The concentrations of suspended sediment in the samples ranged from less than 1 

mg/L to 2,750 mg/L on June 21, 2005. Streamflow at the time of this maximum concentration 

was 14,100 cfs. Streamflow at the collection time of the sample with the highest sediment 

concentration was close to the highest peak during the whole period of sediment sampling 

(15,300 cfs) and close to the average annual peak flow at this site (16,310 cfs). However, 

significantly higher peaks (up to 44,600 cfs) have been recorded during the operation of the 

Hanalei stream gage. The correlation between instantaneous streamflow and measured 

suspended sediment concentration for the 912 samples was 0.86 (see figure below). 

81
82
Appendix 1. Agenda for the Hanalei Watershed Workshop 

Wednesday, February 21, 2007 

Princeville Resort, Queen Emma Room 

8:00 am Check-In 

8:30 am Introduction 

Welcome by Maka`ala Kaaumoana, Executive Director, Hanalei Watershed Hui 

Hawaiian Pule by Stacy Sproat-Beck 

Opening Remarks by Carl Berg and Mike Field 

8:45 am Morning Discussion Sessions 

Session 1: How sediment is generated in the watershed 

Moderator: Carl Berg 

Presenters: Jim Jacobi, Pat Chavez, Ron Bingner/Fred Theurer, Paul Pedone, Ali 

Fares, Chris Smith/Katina Hanson, and Matt Rosener 

10:00 am Short Break 

Session 2: How sediment is transported in the watershed 

Moderator: Mike Field 

Presenters: Ron Bingner/Fred Theurer, Pat Chavez, and Gordon Tribble 

12:00 pm Lunch 

1:30 pm Afternoon Discussion Sessions 

Session 3: Deposition of sediment in the lower watershed 

Moderator: Gordon Tribble 

Presenters: Mike Field 

3:00 pm Short Break 

Session 4: Deposition of sediment in the Bay and beyond 

Moderator: Paul Jokiel 

Presenters: Mike Bothner, Rich Reynolds, Amy Draut/Mike Bothner, Mike Field, 

Curt Storlazzi, and Ron Hoeke 

5:00 pm Pau Hana Gathering, Hanalei Pavilion Beach Park 

83
Thursday, February 22, 2007 

Princeville Resort, Queen Emma Room 

8:30 am Morning Discussion Sessions 

Session 5: Flow of nutrients and pathogens via groundwater and surface flow 

Moderator: Audrey Shileikis 

Presenters: Karen Knee, Ron Bingner/Fred Theurer, Scott Carr, Carl Orazio, Dave 

Penn/Andrew Parker, and Carl Evensen 

10:00 am Short Break 

Session 6: How terrestrial and aquatic ecosystems have been affected 

Moderator: Jim Jacobi 

Presenters: Paul Jokiel, Jim Jacobi, Greta Aeby, Eric Brown/Carl Berg, Alan 

Friedlander/Carl Berg, and Linda Koch 

With additional comments by: Fred Theurer and Laetitia Hédouin 

12:00 pm Lunch 

1:30 pm Afternoon Discussion Sessions 

Wrap-up of Sessions 1 through 6 

3:00 pm Short Break 

Session 7: What management actions are needed to improve water quality and reduce 

pollution threats to corals? 

Moderators: Wendy Wiltse 

Presenters: Kathy Chaston, Dave Penn, and Audrey Shileikas 

Group discussion and comments on management issues 

4:30 pm Closing Discussion and Comments: Mike Field and Carl Berg 

5:00 pm Pau 

84
Appendix 2. List of Workshop Contributors

NAME ORANIZATION LOCATION EMAIL 

Aeby, Greta UH-HIMB HI greta@hawaii.edu

Ambagis, Steve UH-HSCU Hilo HI sambagis@usgs.gov

Bacon, Scott Princeville Hotel HI jscottbacon@hawaiiantel.net 

Berg, Carl Hanalei Watershed Hui HI cberg@pixi.com

Bingner, Ronald USDA-ARS Oxford, MS rbingner@msa-oxford.ars.usda.gov 

Boehm, Alexandra Stanford University Palo Alto, CA aboehm@stanford.edu

Bothner, Mike USGS-CMG Woods Hole, MA mbothner@usgs.gov 

Brown, Eric NPS Kalaupapa, HI Eric_Brown@nps.gov 

Carr, Scott USGS-CERC Corpus Christi, TX Scott.Carr@tamucc.edu 

Carter, Jamie NOAA-PCSC HI Jamie.Carter@noaa.gov

Chaston, Kathy UH HI chaston@hawaii.edu

Chavez, Pat USGS-GEO Flagstaff, AZ pchavez@usgs.gov

Cochran, Susan USGS-CMG Santa Cruz, CA scochran@usgs.gov

de Buhr, Evelyn Hanalei Watershed Hui HI fdredb@hawaiian.net 

Draut, Amy USGS-CMG Santa Cruz, CA adraut@usgs.gov 

Dyda, Rachael Stanford University Palo Alto, CA rydyda@pangea.stanford.edu 

El-Kadi, Aly UH-NREM HI aly@soest.hawaii.edu 

Evensen, Carl UH-NREM HI evensen@hawaii.edu 

Fares, Ali UH-NREM HI afares@hawaii.edu

Field, Michael USGS-CMG Santa Cruz, CA mfield@usgs.gov

Friedlander, Alan NOAA-NOS HI afriedlander@oceanicinstitute.org 

Hanson, Katina USDA-NRCS HI katina.hanson@hi.usda.gov 

Hawkes, Mike FWS HI mike_hawkes@fws.gov 

Hédouin, Laetita UH HI laetitia@hawaii.edu

Hill, Barry USGS-WRD HI brhill@usgs.gov 

Hoeke, Ron NOAA-CRED HI ronald.hoeke@noaa.gov

Imparato, Carl Hanalei Watershed Hui HI Carl.Imparato@juno.com 

Jacobi, Jim USGS-BRD HI jim_jacobi@usgs.gov

Jokiel, Paul UH-HIMB CRAMP HI jokiel@hawaii.edu

Kaaumoana, Maka`ala Hanalei Watershed Hui HI makaala@hawaiian.net 

Knee, Karen Stanford University Palo Alto, CA klknee@gmail.com

85
NAME ORANIZATION LOCATION EMAIL 

Koch, Linda DOH-EHA TMDL HI linda.koch@doh.hawaii.gov

Kubo, Dudley USDA-NRCS HI dudley.kubo@hi.usda.gov

MacGowan, Petra DAR-NOAA Coral Fellow HI Petra.MacGowan@hawaii.gov 

Marrin, West Surfrider HI marrin@watersciences.org 

Michaud, Jene UH-Hilo HI jene@hawaii.edu 

Mikuni, Alan USGS-GEOG Menlo Park, CA amikuni@usgs.gov 

Minton, Dwayne FWS HI Dwayne_Minton@fws.gov 

Mira, Monika East HI Soil and Cons. HI monika.mira@hi.nacdnet.net

Mitchell, Mike FWS HI Mike_Mitchell@fws.gov 

Moore, Dan USDA-NRCS Portland, OR Dan.Moore@por.usda.gov 

Nipper, Marion Texas A&M Corpus Christi, TX Marion.Nipper@tamucc.edu 

Okubo, Watson DOH HI watson.okubo@doh.hawaii.gov 

Orazio, Carl USGS-CERC Columbia, MO corazio@usgs.gov

Parker, Andrew Tetra Tech VA andrew.parker@tetratech-ffx.com 

Paytan, Adina Stanford University Palo Alto, CA apaytan@pangea.stanford.edu

Pedone, Paul USDA-NRCS Portland, OR Paul.Pedone@or.usda.gov

Penn, David DOH-EHA TMDL HI david.penn@doh.hawaii.gov

Quan, Quan USDA-NRCS Beltsville, MD quan.quan@wdc.usda.gov

Reynolds, Richard USGS-GD Boulder, Co rreynolds@usgs.gov 

Riggle, Lex USDA-NRCS HI Lex.Riggle@hi.usda.gov 

Ritchie, Jerry USDA-ARS Beltsville, MD jerry.ritchie@ars.usda.gov

Rodgers, Ku`ulei University of Hawai`i HI kuuleir@hawaii.edu 

Rosener, Matt Hanalei Watershed Hui HI laminarmatt@hawaiiantel.net

Rubin, Dave USGS-CMG Santa Cruz, CA drubin@usgs.gov

Shileikis, Audrey EPA San Francisco, CA shileikis.audrey@epa.gov

Shipp, Allison USGS-Western Region Klamath Falls, OR aashipp@usgs.gov

Slay, Hudson DOH HI Hudson.slay@doh.hawaii.gov 

Smith, Chris USDA-NRCS HI chris.smith@hi.usda.gov 

Smith, Gordon FWS HI Gordon_Smith@fws.gov 

Stock, Jon USGS-ESP Menlo Park, CA jstock@usgs.gov 

Storlazzi, Curt USGS-CMG Santa Cruz, CA cstorlazzi@usgs.gov

Street, Joseph Stanford University Palo Alto, CA jstreet@stanford.edu 

Theurer, Fred USDA-NRCS Gaithersburg, MD fred.theurer@verizon.net 

Tribble, Gordon USGS-WRD HI gtribble@usgs.gov

86
NAME ORANIZATION LOCATION EMAIL 

Ueunten, Gary DOH HI gary.ueunten@doh.hawaii.gov 

Webb, Leah FWS HI Leah_Webb@fws.gov 

Wiltse, Wendy EPA HI Wiltse.Wendy@epamail.epa.gov 

Yates, Lindsay NOAA-NMFS HI Lindsay.Yates@noaa.gov 

Zaun, Brenda FWS HI Brenda_Zaun@fws.gov 

87