NAMBE FALLS RESERVOIR

2004 SURVEY

FT

U.S. Department of the Interior

Bureau of Reclamation
REPORT DOCUMENTATION PAGE Form Approved

0MB No. 0704-0188

1. AGENCY USE ONLY (Leave Blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED

April 2004 Final _______________________________

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS

Nambe Falls Reservoir PR

2004 Survey

6. AUTHOR(S)

Ronald L. Ferrari ________________________

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION

Bureau of Reclamation, Technical Service Center, Denver CO 8 0225-0007 REPORT NUMBER

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING

Bureau of Reclamation, Denver Federal Center, P0 Box 25007, AGENCY REPORT NUMBER

Denver CO 80225-0007 DIBR

11. SUPPLEMENTARY NOTES

Hard copy available at Bureau of Reclamation Technical Service Center, Denver, Colorado

12a. DISTRIBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

13. ABSTRACT (Maximum 200 words)

The Bureau of Reclamation (Reclamation) surveyed Nambe Falls Reservoir in the spring of 2004 to develop new reservoir

topography and compute a present storage-elevation relationship (area-capacity tables). The underwater survey, conducted near

lake elevation 6,803 feet (project datum), used sonic depth recording equipment interfaced with a real-time kinematic (RTK)

global positioning system (GPS) that gave continuous sounding positions throughout the underwater portion of the reservoir

covered by the survey vessel. The above-water topography was developed by standard land collection methods using RTK GPS

and total station instrumentation. This study assumed no change, since the 1976 Original reservoir survey, from elevation 6,828

(feet) and above due to the lack of detailed 2004 above water data.

As of April 2004, at spiiway crest elevation 6,826.6, the surface area was 58 acres with a total capacity of 1,920 acre-feet. Since

dam closure on February 23, 1976, about 106 acre-feet of estimated change has occurred below elevation 6,826.6, resulting in a

5.2 percent loss in reservoir volume. This calculated change is due to sediment inflow and accuracy differences between the

surveys. The study calculated that 42.5 percent of the total change occurred below dead storage elevation 6,760.9.

14. SUBJECT TERMS 15. NUMBER OF PAGES

reservoir area and capacity! sedimentation! reservoir surveys/ sonar! sediment distribution! _____________________

contour area! reservoir area! sedimentation survey! global positioning system! lake 16. PRICE CODE

17. SECURITY 18, SECURITY 19. SECURITY CLASSIFICATION 20. LIMITATION OF

CLASSIFICATION CLASSIFICATION ABSTRACT

OF REPORT OF ABSTRACT

OF THIS PAGE

UL Ut Ut

_____________________

UL _______________________ __________________

NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89)

Prescribed by ANSI SId. 239-18

- 298-102
Nambe Falls Reservoir

2004 Survey

By

Ronald L. Ferrari

Sedimentation and River Hydraulics Group

Water Resources Services

Technical Service Center

Denver, Colorado

April 2004
ACKNOWLEDGMENTS

The Bureau of Reclamation's (Reclamation) Sedimentation and River

Hydraulics Group of the Technical Service Center (TSC) prepared and

published this report. Anthony Lopez of the Albuquerque Area Office

(AAO) was the team leader for this study. Ronald Ferrari of the TSC and

Anthony Lopez and Anthony Vigil of the AAO conducted the

hydrographic survey. Ron Ferrari of the TSC completed the data

processing needed to generate the new topographic map and area-capacity

tables. Sharon Nuanes of the TSC developed the final topographic map.

Kent Collins of the TSC performed the technical peer review of this

documentation.

UNITED STATES DEPARTMENT OF TILE

INTERIOR

The mission of the Department of the Interior is to protect

and provide access to our Nation's natural and cultural

heritage and honor our trust responsibilities to Indian tribes

and our commitments to island communities.

BUREAU OF RECLAMATION

The mission of the Bureau of Reclamation is to manage,

develop, and protect water and related resources in an

environmentally and economically sound manner in

the interest of the American public.

The information contained in this report regarding commercial products

or firms may not be used for advertising or promotional purposes and is

not to be construed as an endorsement of any product or firm by

Reclamation. The information contained in this report was developed for

the Bureau of Reclamation; no warranty as to the accuracy, usefulness, or

completeness is expressed or implied.

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CONTENTS

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Page

Introduction 1

Summary and Conclusions 2

Reservoir Operations 3

Hydrographic Survey Equipment and Method 3

Reservoir Area and Capacity 5

Topography Development 5

Development of 2004 Contour Areas 6

2004 Storage Capacity 6

Reservoir Sediment Analyses 7

Summary and Recommendations 9

References 9

TABLES

Table

1 Reservoir sediment data summary (page 1 of 2) 11

1 Reservoir sediment data summary (page 2 of 2) 12

2 Summary of 2004 survey results 13

FIGURES

Figure

1 Nambe Falls Reservoir location map 1

2 Nambe Falls Reservoir 2004 data map 15

3 Nambe Falls Reservoir topographic map 17

4 2004 area and capacity curves 19

5 Nambe Falls (After 2004 Survey) 20

111
INTRODUCTION 

Nambe Falls Dam and Reservoir, on the Rio Nambe River, are within the boundaries of the Rio 

Nambe Indian Reservations in Santa Fe County. The dam, reservoir, and facilities are part of the 

San Juan-Chama Project and are located about 12 miles north of Santa Fe, New Mexico (fig. 1). 

Heron NPavF\ JElVrnlo 

Elaphant Butt "La 

NEW MEXICO 

Figure 1 - Nambe Falls Reservoir Location Map. 

The reservoir, formed by a concrete arch and earthfill dam, had initial storage on February 23 of 

1976. The zoned earth embankment dam has a 673-foot long crest at elevation of 6,844.0, a 

structural height of 144 feet, and a hydraulic height of 127 feet. The concrete arch dam 

dimensions are: 

Hydraulic height1 

Top width 

Crest elevation 

feet 

feet 

feet2 

Structural height 

Crest length 

150 feet 

320 feet 

1 The definition of such terms as "hydraulic height," "structural height," etc. may be found in manuals such as Reclamation's 

Design of Small Dam and Guide for Preparation of Sanding Operating Procedures for Dm and Reservoirs, or ASCE's 

Nomenclature for Hydraulics. 

2 Elevations are in feet. All elevations in this report are based on the original project datum established by U.S. Bureau of 

Reclamation that was reported to be tied to the National Geodetic Vertical Datum of 1929 (NGVD29). 
The spillway is an uncontrolled overflow section in the center of the arch dam with crest

elevation 6,826.6 and provides a discharge of 22,500 cubic feet per second (cfs) at maximum

reservoir elevation 6,839.8. An outlet works is located through the arch dam and consists of two

18-inch-diameter and one 6-inch-diameter conduits. The inlet elevation of the outlets is 6,761.5

with a discharge capacity of 107 cfs at reservoir elevation 6,826.6.

The drainage area above Nambe Falls Dam is approximately 34.1 square miles with all

considered sediment contributing. The drainage area is orientated east to west on the western

slope of the Sangre de Christo Mountains and ranges from elevation 6826.6, at the spillway crest,

to over 12,600 feet along the eastern rim of the basin. Tn June 2003, a major basin fire affected

about 1.5 square miles or 4.4 percent of the basin (Bureau of Indian Affairs, September 2003).

The reservoir is about 0.7 miles in length with an average width of around 0.13 miles.

SUMMARY AND CONCLUSIONS

This Reclamation report presents the 2004 results of the survey of Nambe Falls Reservoir. The

primary objective of the survey was to gather data needed to:

• develop reservoir topography

• compute area-capacity relationships

• estimate sediment deposition since dam closure in 1976

The hydrographic survey crew used the horizontal and vertical control that was previously

established as part of the Nambe Dam settlement and deflection network. The GPS base was set

over monument "G" (located on the downstream face of the earthen portion of the dam) that was

last surveyed in April of 2003. The horizontal control was in the New Mexico state plane central

coordinate zone in the North American Datum of 1927 (NAD27) and the vertical control was

tied to the National Geodetic Vertical Datum of 1929 (NGVD29). All elevations in this report

are in feet and referenced to the Reclamation project vertical datum that is reported to be tied to

NGVD29.

The underwater survey, conducted on March 30 and 31 of 2004, was between reservoir

elevations 6,803.1 and 6,803.4. The bathymetric survey used sonic depth recording equipment

interfaced with a RTK GPS capable of determining sounding locations within the reservoir. The

system continuously recorded depth and horizontal coordinates of the survey boat as it navigated

along grid lines covering Nambe Falls Reservoir. The positioning system provided information

to allow the boat operator to maintain a course along these grid lines. Water surface elevations

recorded by the Reclamation's reservoir gauge, during the time of collection, were used to

convert the sonic depth measurements to true reservoir bottom elevations. The above-water

topography was determined by standard land collection methods using RTK GPS and total

station instrumentation. For final map development, a digitized the water surface contour from

the U.S. Geological Survey quadrangle (USGS quad) map of the reservoir area was utilized.

2
The 2004 Nambe Falls Reservoir topographic map is a combination of the above and under water

2004 collected data and the digitized USGS quad contour. A computer graphics program

generated the 2004 reservoir surface areas at predetermined contour intervals from the collected

reservoir data.

The 2004 area and capacity tables were generated by a computer program that uses measured

contour surface areas and a curve-fitting technique to compute area and capacity at prescribed

elevation increments (Bureau of Reclamation, 1985).

Tables 1 and 2 contain summaries of the Nambe Falls Reservoir and watershed characteristics for

the 2004 survey. The 2004 survey determnied that the reservoir has a storage capacity of 1,920

acre-feet and a surface area of 58 acres at spillway crest elevation 6,826.6. Since closure on

February 23, 1976, the reservoir has an estimated volume change of 106 acre-feet below

reservoir elevation 6,826.6. This volume represents a 5.2 percent loss in total capacity at this

elevation.

RESERVOIR OPERATIONS

Nambe Falls Reservoir is part of the San Juan-Chama Project that provides a water supply to the

middle Rio Grand Valley for municipal, domestic, and industrial uses. The April 2004 capacity

table shows 2,792 acre-feet of total storage below the maximum water surface elevation 6,839.8.

The 2004 survey measured a minimum lake bottom elevation of 6,740.5. The following values

are from the April 2004 capacity table:

• 872 acre-feet of surcharge elevation 6,826.6 and 6,839.8.

• 1,618 acre-feet of active conservation use between elevation 6,780.0 and 6,826.6.

• 224 acre-foot of inactive storage between elevation 6,760.9 and 6,780.0.

• 78 acre-foot of dead storage below 6,760.9.

Nambe Falls Reservoir available inflow and end-of-month stage records are listed on table 1 for

operation period 1976 through 2004. The inflow values are from the USGS gauging station "Rio

Nambe below Nambe Falls Dam." This station is located below the dam, but was the only

available information during preparation of this report. The average runoff at this gauge for

water years 1979 through 2001 was 10,310 acre-feet per year. The table shows the extreme

annual fluctuation of the reservoir as the water surface exceeded spillway crest elevation 6,826.6

many years. The maximum-recorded elevation was 6,827.2 in 1979 with the minimum elevation

of 6,778.8 in 1996.

HYDROGRAPHIC SURVEY EQUIPMENT AND METHOD

The survey of Nambe Falls Reservoir was first planned for spring 2003, but was delayed because

the 2003 low runoff did not provide full reservoir conditions. Full reservoir conditions are ideal

3
for a hydrographic survey, if dense above water collection will not be conducted, because the

survey vessel can cover the underwater portion in a more efficient manner than standard land

methods. During the summer of 2003, an extensive drainage basin fire occurred and the resulting

runoff deposited material within the reservoir boundary. During the winter of 2003, the reservoir

was lowered to excavate the exposed sediments. Tn January of 2004, a request was made to

conduct the hydrographic survey at an extremely low lake level, near elevation 6,786, but icy

conditions made collection very hazardous so it was delayed until late March of 2004. Tn March,

the lake had risen to elevation 6,803, but still required much above water collection. During

collection, the hydrographic crew found some of the excavated reservoir material deposited in

mounds within the reservoir boundary with some completely exposed and some just below the

water surface. Limited data was collected on and around these deposits for future reference. It is

predicted that much of this material will be eroded over time from its present location and will

deposit in lower elevations of the reservoir.

The bathymetric or underwater water survey equipment was mounted on a small boat with an

outboard motor. The hydrographic system included a RTK GPS receiver with a built-in radio, a

depth sounder, a computer, hydrographic system software for collecting the underwater data, and

12-volt batteries to power the instrumentation. The shore equipment included a second RTK

GPS receiver with an external radio powered by a 12-volt battery. The GPS antenna was

mounted on a survey tripod over the known datum point "G".

The Sedimentation and River Hydraulics Group uses RTK GPS. The major benefit of RTK GPS

is precise height measurement in real time to monitor water surface elevation changes. The basic

outputs from a RTK receiver are precise 3D coordinates in latitude, longitude, and height with

accuracies on the order of 2 centimeters horizontally and 3 centimeters vertically. The output is

on the GPS datum of WGS-84 that the hydrographic collection software converted into New

Mexico's NAD27 central state plane coordinates. The RTK GPS system employs two receivers

that track the same satellites simultaneously just like with differential GPS.

Nambe Falls Reservoir hydrographic survey was conducted on March 30 and 31 between water

surface elevations 6,803.1 and 6,803.4 (Reclamation project datum). The bathymetric survey

used sonic depth recording equipment, interfaced with a RTK GPS, capable of determining

sounding locations within the reservoir. The survey system software continuously recorded

reservoir depths and horizontal coordinates as the survey boat moved across closely spaced grid

lines covering the reservoir area. Most transects (grid lines) were run in a perpendicular

alignment of the reservoir at around a 50-foot spacing. Data also was collected along the shore

as the boat traversed between transects. Extensive amounts of surface debri hindered full access

by the survey boat near the concrete portion of the dam. The survey vessel's guidance system

gave directions to the boat operator to assist in maintaining the course along these predetermined

lines. During each run, the depth and position data were recorded on the notebook computer

hard drive for subsequent processing. The collected data was digitally transmitted to the

computer collection system via a RS-232 port.

The underwater collected data was processed using the same hydrographic system software that

was used for the onboard data collection. The analysis included applying all measurements, such

4
as vessel location, and corrections that included the sound velocity of the reservoir water column,

and converting all depth data points to elevations using the measured water surface elevation at

the time of collection. The depth sounder produced digital charts of the measured depths that

were analyzed during post-processing for correcting errors in the computer recorded bottom

depths. The water surface elevations at the dam, recorded by a Reclamation gauge and

confirmed by the RTK GPS ground survey, were used to convert the sonic depth measurements

to true lake-bottom elevations. The underwater data set from the single beam depth sounder

included around 18,000 data points.

The above water area of the reservoir was surveyed by standard land collection methods using

both a RTK GPS rover and total station instrumentation. Since there was only one rover

available, a total station was used when the RTK GPS rover was being utilized for the

underwater collection. The above water data set included about 4,000 data points.

All data was tied to the existing Nambe Falls Reservoir control network that was last surveyed in

April of 2003. The horizontal control was in the New Mexico state plane central coordinate zone

in the North American Datum of 1927 (NAD27) and the vertical control was tied to the National

Geodetic Vertical Datum of 1929 (NGVD29). During the RTK GPS collection, the base was set

over point "G" and checked on other network points such as "F" and "K". Following are

coordinates for points used during the 2004 reservoir survey:

F G K

East 602,383.60

North 1,762,850.56

Elevation 6,842.436

602,301.04

1,762,975.14

6,843.971

RESERVOIR AREA AND CAPACITY

Topography Development

602,328.98

1,762,886.70

6,841.275

The topography of Nambe Falls Reservoir was developed from the 2004 collected data and the

digitized contour from the USGS quad maps. The digitized USGS contour line was the Nambe

Falls Reservoir contour that outlined the reservoir boundary and was developed from imagery

taken in 1996. ARC/INFO V7.0.2 geographic information system software was used to digitize

the USGS quad contour. The digitized contours were transformed to New Mexico's NAD 1927

state plane coordinates, central zone, using the ARC/INFO PROJECT command.

The digitized contour line was used to perform a clip of the Nambe Falls Reservoir triangular

irregular network (TIN) such that interpolation was not allowed to occur outside the enclosed

polygon. The selected contour was the closest available data to the actual reservoir water

surface. This clip was performed using the hardclip option of the ARC/INFO CREATETIN

5
command. Using ARCEDIT, the 2004 collected data and digitized contours from the quad maps

were plotted. The plot showed that the underwater data did not lie completely within this clip,

which required modifications to include the entire underwater data set within the enclosed

polygon. Modified areas included some of the shoreline and small inlets not shown on the USGS

quad. Using SELECT and MOVE commands within ARCEDIT, the vertices of the clip were

shifted to fit all the 2004 collected reservoir data. This hardclip was assigned an elevation of

6,828 to reflect the original surface area of this developed polygon. A plot of the 2004 collected

data and the generated contour, elevation 6,826, are shown on figure 2.

Contours for the reservoir below elevation 6,828.0 were computed from the 2004 data set using

the triangular irregular network (TIN) surface-modeling package within ARC/INFO. A TIN is a

set of adjacent non-overlapping triangles computed from irregularly spaced points with x,y

coordinates and z values. TIN was designed to deal with continuous data such as elevations.

The TIN software uses a method known as Delaunay's criteria for triangulation where triangles

are formed among all data points within the polygon clip. The method requires that a circle

drawn through the three nodes of a triangle will contain no other point, meaning that sample

points are connected to their nearest neighbors to form triangles using all collected data. This

method preserves all collected survey points. Elevation contours are then interpolated along the

triangle elements. The TIN method is discussed in greater detail in the ARC/INFO V7.0.2 Users

Documentation, (ESRI, 1992).

The linear interpolation option of the ARC/INFO TINCONTOIJR command was used to

interpolate contours from the Nambe Falls Reservoir TIN. The areas of the enclosed contour

polygons at one-foot increments were developed from the survey data for elevations 6,842.0

through elevation 6,828.0. The 2004 study assumed no change in area since the original survey

for elevation 6,828.0 and above. The contour topography at 2-foot intervals is presented on

figure 3.

Development of 2004 Contour Areas

The 2004 contour surface areas for Nambe Falls Reservoir were computed at 1-foot increments

from elevation 6,841.0 to 6,828.0. The 2004 underwater survey measured a minimum reservoir

bottom elevation of 6,740.5. These calculations were performed using the ARC/INFO

VOLUME command. This command computes areas at user-specified elevations directly from

the TIN and takes into consideration all regions of equal elevation. For the purpose of this study,

the measured 2004 survey areas at 2-foot increments from elevation 6,842.0 through 6,824.0

were used to compute the new area and capacity tables. Due to the limited amount of 2004

above water data, this study assumed no change from the original surveyed areas at elevation

6,828.0 and above.

2004 Storage Capacity

The storage-elevation relationships based on the measured surface areas were developed using

the area-capacity computer program ACAP85 (Bureau of Reclamation, 1985). The 2004

surveyed surface areas at 2-foot contour intervals,from reservoir elevation 6,742.0 to elevation

6
6,824.0 were used as the control parameters for computing the 2004 Nambe Falls Reservoir

capacity. The original computed survey area at elevation 6,828.0 and the original surveyed

surface areas at 5-foot contour intervals from elevation 6,830.0 to 6,840.0 were used to complete

the area and capacity tables. The program can compute an area and capacity at elevation

increments 0.01- to 1.0-foot by linear interpolation between the given contour surface areas. The

program begins by testing the initial capacity equation over successive intervals to ensure that the

equation fits within an allowable error limit. The error limit was set at 0.00000 1 for Nambe Falls

Reservoir. The capacity equation is then used over the full range of intervals fitting within this

allowable error limit. For the first interval at which the initial allowable error limit is exceeded, a

new capacity equation (integrated from basic area curve over that interval) is utilized until it

exceeds the error limit. Thus, the capacity curve is defined by a series of curves, each fitting a

certain region of data. Differentiating the capacity equations, which are of second order

polynomial form, derives fmal area equations:

y = a1 + a2x + a3x2

where: y = capacity

x elevation above a reference base

a1 = intercept

a2 and a3 = coefficients

Results of the Nambe Falls Reservoir area and capacity computations are listed in table 1 and

colunms 4 and 5 of table 2. On table 2, columns 2 and 3 list the original surface areas and

recomputed original capacities. A separate set of 2004 area and capacity tables has been

published for the 0.01, 0.1 and 1-foot elevation increments (Bureau of Reclamation 2004). A

description of the computations and coefficients output from the ACAP85 program are included

with these tables. Both the original and 2004 area-capacity curves are plotted on figure 4. As of

April 2004, at maximum reservoir elevation 6,839.8, the surface area was 74 acres with a total

capacity of 2,792 acre-feet.

RESERVOIR SEDIMENT ANALYSES

Figure 4 is a plot comparison of the surface areas and capacities of Nambe Falls Reservoir's

original and 2004 survey results. For calculating the 2004 sediment accumulation, the original

capacities were recomputed using ACAP85. ACAP85 was also used to compute the 2004

capacities. Using the same program removes the small computation differences that occur

between programs. Since Nambe Dam closure in 1976, the measured total volume change at

reservoir elevation 6,826.6 is 106 acre-feet. The estimated average annual rate of capacity lost

for the 28.1-year operation period was 3.8 acre-feet per year. The storage loss in terms of percent

of original storage capacity was 5.2 percent at elevation 6,826.6.

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The original survey measured a minimum elevation of 6,667 and the 2004 survey measured the

minimum at the dam as elevation 6,740.5. This indicates over 70 feet of sediment deposition at

the dam, but it must be noted the original survey only measured a surface area of 0.1 acres at

elevation 6,710 and 1.1 acres at elevation 6,735. Of the total measured sediment in 2004, about

9.4 percent has deposited from elevation 6,735 and below and about 42.5 percent has deposited

in the dead storage area below elevation 6,760.9. Figure 5 illustrates the 2004 sediment

accumulation in relation to the outlet location and the reservoir pooi elevations.

The Nambe Falls reservoir capacity allocation sheet lists the 1 00-year sediment deposition to be a

total of 400 acre-feet below elevation 6,826.6 of which 230 acre-feet, or 57.5 percent, is

projected to deposit below elevation 6,780.0. The 100-year estimate equates to 4 acre-feet per

year, which is close to the 2004 survey result of 3.8 acre-feet per year. The 2004 survey results

measured a normal accumulation pattern compared to the 100-year projections, but the June 2003

drainage fire could affect the sediment accumulation over the next few years.

As indicated previously, the 2004 area and capacity tables were generated assuming no change in

area and capacity, since the 1976 original survey, from elevation 6,828 and above due to the lack

of above water detailed survey data. This is in all probability not the case, but from the 2004

collected data and visual observation, it appears there has been minimal change at the upper

reservoir elevations since 1976. The 2004 above water survey collected data along the visual

high water mark where it could be safely accessed around the lake. This data was used along

with the USGS digitized contour to generate a hardclip around the reservoir perimeter. This

enclosed clip was assigned elevation 6,828 because it was near the original surface area for this

elevation.

The 2004 survey noted a minimal sediment delta in the upper reservoir area and only a minor

amount of shoreline erosion. The delta that previously existed was excavated in the winter of

2003 and some of this material was deposited within the reservoir boundaries below the spillway

crest elevation of 6,826.6. The land excavation of the reservoir area was conducted when the

water surface was below elevation 6,790. It appears a large portion of the reservoir bottom was

disturbed and a large amount of reservoir bottom material moved and deposited in the eastern

and northern portions of the reservoir. During the 2004 survey, data was collected on land and

underwater to map the locations of these deposits. Most of these spoils will be completely

submerged when the reservoir becomes full and it is predicted that over time the majority of this

material will be redistributed in the lower elevations of the reservoir due to wind and wave

actions.

SUMMARY

A resurvey of Nambe Falls Reservoir should be conducted in the near future if major sediment

inflow events are observed or after several years of normal runoff. Since the basin fire of 2003

changed the stability of the drainage area., the survey should be scheduled to include major runoff

events, but not until the sediment accumulates within the reservoir. If possible, the survey should

be schedule when the reservoir level is nearly full to minimize the need and time required for the

8
above water collection. Range lines could be surveyed to monitor change over time, but the

small reservoir size allows a complete underwater survey, with 50-foot spacing between cross

sections, to be conducted in less than 2-days. The 2004 survey was conducted over a four-day

period, with over fifty percent of that time spent on the above water collection because the

reservoir level was over 20 feet below full. Even though the 2004 land survey only accounted for

about twenty percent of the total data set, it is felt that there was adequate data for the 2004

results to be used as a base for future comparisons. Some of the 2004 upper elevation points

could be used as a base for future surveys.

As noted previously, there was excavation of some of the reservoir area in the winter of 2003

with some of the excavated bottom material deposited within the reservoir boundary. Some of

this deposited material consisted of large rock indicating that areas of original landscape were

disturbed, possibly making it more prone to shoreline erosion. It is felt that over time much of

this spoiled material will be eroded and deposited in the lower elevations of the reservoir. Any

future excavation should remove the material from the reservoir area.

The 2004 survey measured a minimum elevation of 6,740.5; around twenty feet lower than the

inlet elevation of the outlet works. One concern will be the future impact of sediment

accumulation on the outlet works. Future surveys will monitor this change, but other means of

measurement should also be considered. A depth sounder on a boat is one means. Lowering a

weighted marked line tag from the dam might be possible if the deepest portion of the reservoir is

accessible from the abutments. With the top of the parapet wall at elevation 6,844.0, the tag line

would need to be around 110 feet in length.

RECOMMENDATIONS

Due to the June 2003 basin fire, there are concerns of sediment runoff impacting Nambe

Reservoir. Following are recommendations to monitor possible increase in sediment

accumulation for the next few years.

1. Visual observation of sediment accumulation. During low reservoir stage and during or

after major runoff events a site visit should be conducted to visually document possible

changes. Someone familiar with the reservoir such as the dam tender or local office

could conduct this site visit. A trip report with photographs should be filed.

2. If there are concerns from the visual observations, the sediment accumulation impact to

the outlet works may be monitored by lowering a tagline into the deepest portions of the

reservoir near the dam. It may be possible to do this from the dam with a tagline that is

110 feet in length. The tagline could also be lowered from a boat, but a depth sounder as

simple as a fish finder could also be used. The dam tender or local office can perform

these tasks seasonally or as concerns warrant.

3. If it is determined a resurvey is needed, then it should be scheduled when the reservoir is

near full conditions. During the planning of the 2004 survey, several above water

9
methods were researched, but time and funding did not allow their use. These methods

included aerial survey, land base lidar, and additional GPS rovers.

REFERENCES

American Society of Civil Engineers, 1962. Nomen clature for Hydraulics, ASCE Headquarters,

New York.

Bureau of Indian Affairs, September 2003. Molina Complex, Burned Area Emergency

Stabilization and Rehabilitation Plan, Interagency Burned Area Emergency Response Team,

Nambe Pueblo, New Mexico.

Bureau of Reclamation, 1981. Project Data, Denver Office, Denver CO.

Bureau of Reclamation, 1985. Surface Water Branch, ACAP85 User's Manual, Technical

Service Center, Denver CO.

Bureau of Reclamation, 1987(a). Guide for Preparation of Standing Operating Procedures for

Bureau of Reclamation Dams and Reservoirs, U.S. Government Printing Office, Denver, CO.

Bureau of Reclamation, 1987(b). Design of Small Dams, U.S. Government Printing Office,

Denver CO.

Bureau of Reclamation, April 2004. Denver Office, Nambe Falls Reservoir Area and Capacity

Tables, San Juan - Chama Project, Upper Colorado River Region, Salt Lake City, UT.

Corps of Engineers, January 2002. Engineer and Design - Hydrographic Surveying,

EM 1110-2-1003, Department of the Army, Washington DC,

(www.usace.army.mil!inet/usace-docs/eng-manuals/eml 110-2-1 003/toc.htm).

Environmental Systems Research Institute, Inc. (ESRI), 1992. ARC Command Refrrences.

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RESERVOIR SEDIMENT

DATA SUMMARY Nambe Falls Reservoir

NAME OF RESERVOIR 1

DATA SHEET NO.

D 1. OWNER Bureau of Reclamation 2. STREAM Rio Narnbe 3. STATE New Mexico

A 4. SEC. 29 TWP. 19 N RANGE 10 E 5. NEAREST P.O. Nambe Pueblo 6. COUNTY Santa Fe

M 7. LAT 35 50 46" LONG 105" 54' 17" 8. TOP OF DAM ELEVATION 6,840.0' 9. SPILLWAY CREST EL 6,826.62

R 10. STORAGE 11. ELEVATION 12. ORIGINAL 13. ORIGINAL 14. GROSS 15. DATE

E ALLOCATION TOP OF POOL SURFACE AREA, CAPACITY, STORAGE ACRE- STORAGE

S ACRES ACRE - FEET FEET BEGAN

E a. SURCHARGE 6,839.8 74 872 2,898

R

b. FLOOD CONTROL

_________________

V

o

C• POWER _______________

2/23/76

d. JOINT USE _______________ ________________ _______________

16. DATE

R e. CONSERVATION 6,826.6 59 1,666 2,026 NORMAL

f. INACTIVE 6,780.0 18 237 360 OPERATION

g. DEAD 6,760.9 8 123 123 96

-

17. LENGTH OF RESERVOIR Q74 MILES AVG. WIDTH OF RESERVOIR 0.13 MILES

B 18. TOTAL DRAINAGE AREA 34.l SQUARE MILES 22. MEAN ANNUAL PRECIPITATION 8306 INCHES

A 19. NET SEDIMENT CONTRIBUTING AREA 34.l SQUARE MILES 23. MEAN ANNuAL RUNOFF INCHES

S

20. LENGTH 151 AV. WIDTH 129 24. MEAN ANNUAL RUNOFF 10,3108 ACRE-FEET

21. MAX. ELEVAT'7N 10,274 MI N. ELEVATION 4,508 25. ANNUAL TEMP. MEAN °F RANGE -30"F to lO5"F

5 26. DATE OF 27. 28. 29. TYPE OF 30. NO. OF 31. SURFACE 32. CAPACITY 33. C/I

U SURVEY PER. ACCL SURVEY RANGES OR AREA, AC. ACRE-FEET RATIO

R __________________ _______________

V

_________________________________________________ _________________________________

2/23/76 Contour CD) 5-ft 59 2,026 0.20

E

Y

4/1/04 28.1 28.1 Contour CD) 2-ft ss 1,920 0.19

D

26. DATE OF 34. PERIOD 35. PERIOD WATER INFLOW, ACRE FEET WATER INFLOW TO DATE, AF

A SURVEY ANNUAL __________________________________________

T

PRECIP. a. MEAN ANN. b. MAX. ANN. c. TOTAL

_______________

a. MEAN ANN.

_____________

b. TOTAL

A

10, 310'"

26. DATE OF 37. PERIOD CAPACITY LOSS, ACRE-FEET 38. TOTAL SEDIMENT DEPOSITS TO DATE, AF

SURVEY _________________________________________________

a. TOTAL b. AV. ANN. c. /MI.-YR.

________________

a. TOTAL f

___________________

b. AV. ANNUAL

_______________

c. /MI.2-YR.

4/1/04 10611 3.8 0.111 106 3.8 0.111

26. DATE OF 39. AV. DRY 40. SED. DEP. TONS/MI.2-YR. 41. STORAGE LOSS, PCT. 42.

SURVEY MT. (#/FT) ____________________________

a. PERIOD b. TOTAL TO

______________

a. AV.

________________

b. TOTAL TO

______

a.

______

b.

4/1/04 U.lSU

26. 43. DEPTH DESIGNATION RANGE FEET BELOW, AND ANOVE, CREST ELEVATION

DATE

SURVEY 6697- 6760- 6770- 6780- 6790- 6800- 6810- 6820-

6760. 6770 6780 6790 6800 6810 6820 CREST

9

PERCENT OF TOTAL SEDIMENT LOCATED WITHIN DEPTH DESIGNATION

2004 42.5 2.8 9.4 9.5 7.5 11.3 10.4 6.6

26. 44. REACH DESIGNATION PERCENT OF TOTAL ORIGINAL LENGTH OF RESERVOIR

DATE 0-10 10- 20- 30- 40- 50- 60- 70- 80- 90- 100- 105- 110- 115- 120-

Survey 20 30 40 50 60 70 80 90 100 105 110 115 120 125

PERCENT OF TOTAL SEDIMENT LOCATED WITHIN REACH DESIGNATION

Table 1. Reservoir sediment data summary (page 1 of 2)

11
45. RANGE IN RESERVOIR OPERATION8'

YEAR MAX, ELEV. MIN. ELEV. INFLOW, AK YEAR MAX. ELEV. WIN. ELEV. INFLOW, AR

1976 _____________

1977 6,809.5 6,780.6 4,470

1978 6,826.8

______________

6,786.3 6,800 1979 6,827.2 6,798.9 6,600

1980 6,826.9 6,807.8 16,600 1981 6,818.8 6,781.3 3,920

1982 6,817.1 6,785.6 4,280 1983 6,827.1 6,817.1 18,130

1984 6,826.9 6,807.7 12,390 1985 6,827.0 6,814.9 18,640

1986 6,826.7 6,820.2 14,000 1987 6,827.0 6,814.9 15,200

1988 6,826.8 6,814.9 14,000 1989 6,826.6 6,801.4 7,600

1990 6,826.7 6,802.7 6,390 1991 6,827.0 6,826.7 11,730

1992 6,826.8 6,812.4 15,760 1993 6,827.0 6,810.7 11,560

1994 6,827.0 6,804.6 12,370 1995 6,826.9 6,808.3 10,390

1996 6,825.2 6,778.8 5,100 1997 6,826.8 6,789.0 5,200

1998 6,826.8 6,806.4 9,800 1999 6,826.9 6,807.3 9,400

2000 _____________

2001 6,826.9 6,802.8 7,090

2002

______________

_______________ _______________

2003 _______________ _______________ _______________

46. ELEVATION - AREA - CAPACITY DATA FOR (BY INDICATED YEARS) CAPACITY2

ELEVATION AREA CAPACITY ELEVATION AREA CAPACITY ELEVATION AREA CAPACITY

1976 SURVEY 6,667 0 0 6,710 0.1 1

6,715 0.2 1 6,725 0.2 3 6,730 0.6 5

6,735 1.1 10 6,740 2.1 18 6,745 2.9 30

6,750 5.9 50 6,755 6.5 79 6,760 8.0 115

6,760.9 8 123 6,765 9.4 159 6,770 11.2 210

6,775 15.3 277 6,780 17.9 360 6,785 20.5 456

6,790 24.1 567 6,795 27.0 695 6,800 31.3 841

6,805 35.9 1,009 6,810 42.1 1,204 6,815 45.7 1,423

6,820 50.7 1,664 6,825 56.9 1,933 6,826.6 59 2,026

6,830 62.1 2,331 6,835 68.2 2,556 6,839.8 74 2,898

6,840 74.4 2,913

2004 SURVEY

6,740.5 0 0 6,745 1.6 3 6,750 3.4 16

6,755 5.7 39 6,760 7.4 72 6,760.9 8 78

6,765 8.9 112 6,770 11.1 162 6,775 14.0 225

6,780 16.8 302 6,785 19.6 393 6,790 22.9 499

6,795 26.4 622 6,800 30.7 765 6,805 35.1 928

6,810 39.8 1,116 6,815 45.0 1,328 6,820 50.0 1,565

6,826.6 58 1,920 6,830 62.1 2,124 6,835 68.2 2,450

6,839.8 74 2,792 6,840 74.4 2,807

47. REMARKS AND REFERENCES

All elevations are in feet based on the original project datum that app ears to be tied to NGVD29. Top of

earth embankment and parapet wall are at elevation 6844.0.

2 Uncontrolled spillway.

Original values recomputed from 5-foot contours with Reclamation's ACAP program.

' Length with side tributary.

From USGS water year records, 2001. Drainage runoff affected by major fire, June 200 3. Estimated 4.4% of

drainage basin affected, 982 acres (1.5 square miles). From report: " Molina Complex," BIA, 9/200 3.

Bureau of Reclamation Project Data Book, 1981. Values for San Juan - Chama Project.

Calculated using mean annual runoff value of 10,310 AF, item 24. 1979 through 2001 average value from USGS

gage "Rio Nambe Below Nambe Falls Dam." Flows controlled by Nambe Fall s Dam.

8 1979 through 2001 average value from USGS gage "Rio Nambe Below Narnbe Falls Dam." Fl ows affected by Nambe

Falls Dam. Values in item 45 from USGS water reports.

Surface area & capacity at elevation 6,826.6, spiliway crest elevation.

See remarks # 7 and 8. Maximum and minimum elevations from available USGS records by water year.

Total sediment inflow by comparing 2004 survey with recomputed capacity from original survey. Some

computed change due to different methods of survey. 2004 bathymetric c ollection at water surface

elevation 6803. Above water data collected by land survey methods usin g RTK GPS and total station

instruments. During winter of 2003, land equipment excavate reservoir bottom. Some material removed from

reservoir area with some stock piled within reservoir area.

12 All capacities computed by Reclamation's ACAP computer program. The 1976 or origina l capacity values were

recomputed by ACAP for purpose of computing sediment accumulation valu es. 2004 survey assumed no change

from elevation 6,828 and above since original survey.

48. AGENCY MAKING SURVEY Bureau of Reclamation

49. AGENCY SUPPLYING DATA Bureau of Reclamation J

DATE April 2004

Table 1. - Reservoir sediment data summary (page 2 of 2).

12
1 2 3 4 5 6 7 8

20 04 2O 04 percent of

____

Elevations Original Original

Capacity

20042004

Survey Survey

Sed

e

Percent:Reseir

:Sedient

eet):(acre cre-feat) sLjae-feet) (acre - feet)

6,840.0 74.4 2913 74.4: 2807 106

9.8J 2792 1 100.0

835. 2556 06

6,830.0[ 62.1 2231 62.1 2124 107 93.1

6,828.0 60 21091 60.0 2002

6,26.659 2026] 1920 106 100.0 90.8

50.7 156 3.4 86.1

6,815.01 45.7 1423: 45.0 1328 95 __j 6

10 0 42 l 1204 39 8 1116 8 0' 79 1

73 68.9

6,790.0 24.11 567 22.9 499 68 64.2: 65.1

5.0 20.5' 456 19.6 63 59.4

17.9 360

6,775.0 15.31 277 14.0 225 52: 49.1 54.6

0.0 _210 11 162

6,765.0 9.4 159 8.9 112j 47 44.3 47.6

_

8 5 42.5

6,760.0 8.01 115

_

7.4

_

72 431 40.6 44.1

6,755.0 5.7 39 40 37.7 40.6

6,750.0 5.1 50 3.4 16 34: 32.1 37.1

6,745.0 2.9 30 1.6 3 33.6

6,740.0 2.1 [ 18 0.0 0 18 17.0 30.1

,710.0.1 1 0 01 1 9.1

6, 697 . 0 0.0 0 0.0 0 . 0 _______

lElevationofreservoirwatersurface. I ______

2 Original reservoir surface areas from 4/1/1976 memorandwn.

3Originalcapacity recomputedusingACAPto compute sediment accumulatiJ__

JReservoir surface area from 2004 survey.

_________

54Reservo.r capacity

6Measuredsediment

computed

volume.

using_ACP.

column(3)-colunm(5) . : 7Measured sediment expressed in percentage of total sediment 106 acrea-feet.

8 Depth of reservoir expressed in percentage of total depth of 142.8 feet.

Table 2. - Summary of 2004 survey results

13
0

0

0

o0

0

0

0

0

00 • 0

* # 5765000+ 0

s70506m4- 0

o'

00

0

0 0 0

6

0

0

00

0

6' 0

0 0

O 0 665 0

8 0

0

0

a 0 0

0

\

0000

0

J

000

00

0

00000000

N iii 00

:0

°

0

0 00

W

I

0

0

0

ko/, I.fV & 0

0

o' /oF

Spiliway c'o'/ 0 '\ 4

O7 trt

,0,000 I/O

: 0 \\ç. Horizontal datum based on New Mexicos

o 00 \ -' State Plane Coordinate System.

0 0 Central Zone (NA027)

Vertical datum based on original

project datum based on National

o 0

Geodetic Vertical Datum of 1929.

•1*t, 0 0

0 1765000+

Nambe o O

Falls 6

Dam 0 'oo\

0

0

0

00 0

:0

00

0

,

oo

000

0

O

0

%0o

0

0e

OO

O

'0

& 0

0 %OP

, 0

0 .110%

0

A46' RS(Rfl2Ii

0 0 0

0

5700050+ &

0

707000+ 5707000± 2Dt L,4 4M7 lliVi2FPM1TFP i24T4

J[CI#/ICAL APPoML_____

0 Q00 AOVFD__

0

0

-O -- _____________________ ___________________________________________________

nref, Cc/oic+ APR7I, !OOl

15

Figure 2. - Nambe Falls Reservoir 2004 imderwater data.
N

w E

S

ft

ISO .51 ISO

5-_/ kSjP

176&000+

Spiliway

Nambe

Pal is

Dam _______

76OOO*

14

Horizontal datum based on New .lexico's

State Plane Coordinate System.

Central Zone (NA027)

Vertical datum based on original

project datum based on National

Geodetic Vertical Datum of 1929.

17

Figure 3. - Nambe Falls Reservoir topographic map.
--

Area-Capacity Curves for Nambe Falls Reservoir

Area (acre)

80 76 72 68 64 60 56 52 48 44 40 36 32 28 24 20 16 12 8 4 0

6,845.0

6,825.0

6,805.0

0

6,785.0

0

4-.

- >

0

w

6,765.0

6,745.0

0

6,725.0

CD

C)

6,705.0

_7411:

Capacity Area

__________ ________ 2004 Survey __________ __________ ____

Original Survey

0 300 600 900 1200 1500 1800

Capacity (acre-feet)

6,825.0

6,805.0

6,785.0

6,765.0

6,745.0

6,725.0

- -_____ ------- ____------ 6,705.0

2100 2400 2700 3000
Nambe Falls (After 2004 Survey) 

Figure f - Naanbe Falls (Afbr 2004 Survey)