LM-Alaska Open File Rep 

Upper Coiville iver Channel 

th Survey 

au of Land Mana 
CONTENTS 

MSTWCT*..o..........o..........e.* 

I~ROD~CTION*~~*~e*~~~~*

METEODS .oa*ma.**.***e*-m**moornee.o* 

msaTs ~I~~ss~~~ S 4 * * V 8 0 * 

River chamel depths . . . . . . . * . . . . . . . . 

Aerial photography . . . . * . . . . . . . . . . . 

River bluff depth associati~ns . . . . . . a . . 

Side Looking Airborne Radar* . . . . . . . . . . . . 

Fish.....*.,..**,.,......*... 

Page 

1 

Lacation of Colville River float trtp within the 

National Fetrolem Resene-Alaska* . . . . . . . . . 

Illustration of raft navigation used to record 

depth and method used to iaterpret distances of 

rtver channel at or below 2 and 3 meters . . . . . . . 

Illustration of fathometer record analysis/ 

interpretation for riffles . . . . . . . . . . . . . 

Cnlville River Float depicted in 3 contiguous 

sections with deep water channels, river bluffs, 

and major tributaries annotated* . . . . . . . . . . 

TABLES 

Water depth data along upper Colville Riverm . . . . 

Carrela~ion between deep water areas and 

bluffs along upper CaLvi.lle ~~ero . . . . + . . 
Mver channel depths of the upper Colville fiver were surveyed 

during a float trip in late July, 1979* The entire float traversed 152 

kilometers of river* Forty-nine kilameters of cantinuous river channel 

depth recurdings were used to calculate that 23 percent of the river 

was riffle? 57 percent was greater tha~~riffle depth yet less than 2 

meters? 20 percent was 22 meters, and 4.6 percent was 23 meters deep. 

River channel fathometer depths recorded throughout the four day float 

trip are summarized. The maximm recorded water depth was 7 meters. 

The average of all maxhum channel depths for the river pools surveyed 

was 3.6 meters. Deep pools were assaciated with every river bluff 

surveyed. The benefits and shortcondngs of l: 60,000 scale aerial photography and l:2509000 scale Side Looking Airborne Radar (SLAR) imagery, 

used as aids in this type af survey7 are discussed4 

One hundred fifty two kilometers (94.4 miles) of the upper Colville 

River was floated by two individuals during the summer of 1979 ~5th a 

twofold purpose. Raptor and aquatic habitat were assessed3 during the 

four day float trip. 

Pat Reynold's primary effort was dizected toward surveying raptor 

habitat and nesting successe A total of sixty cliff nesttng raptors 

were recorded along the 152 kilometers floated (Reynolds, 1980). This 

included one active peregrine falcon eyrie, one active gyrfalcon eyrie? 

nine active rough-legged hawk nests9 and other nonpaired adult raptors. 

Other wildlife (i*em9 bear, caribou, moose7 and waterfowl) were sighted 

and recorded aLorig the raute* Faunal, records for this trip are available from Pat Reymlds and her report on file at the Bureau of Land 

Xanagement N?R-A9 Fairbanks District Of %iceThe authorrs primary purpose was to record water depth along the 

CdviLle River from which potential overwintering fish habitat could be 

assessed. Fathameter records were used for analyzing, documenting, and 

finally charting the locations of deep water habitat alang the active 

river channel sumeyed. Once the locations of deep water habitat were 

charted? these daca were analyzed to determine the percentage of river 

with potential for fish overwintering areas verus shallow and riffle 

areas. In additiun, the charted river depths were compared with remotesensing data of this Colville River area to ascertain the applicability 

of utilizing aerial photography and/or Side Looking Airborne Radar 

(SW) imagery for some river depth determinations. 
NATIONAL PETROLEUM RESERVE 
-- 

The section of River surveyed was a se&&- of pools separated by 

shallow riffles (Lm 3m). After freezeup, free water in deep channels 

is present in winter pools below a growing ice sheet and between. frozen 

shoals, Pools exceeding mabm winter ice thickness (321~) are potential 

grayling overwintering amas. This species dominates the wintering 

habitat in the upper Colville Rive?. Once depths axe detemined and 

deep versus shallow water habitat quantified9 we can better estimate 

impacts from a specif5ed aceion disturbing any river 1ocaLity. 

This survey started approximately 350 air kilometers from the 

mouth of the CoLvilLe, the largest of Alaskan arctic rivers. It began 

on the Culville half way between the confluence of the Nuka and Kiligwa 

Rivers (Fig* 1). The Nuha River was the only major tributary between 

the starting point and the headwaters of the Colville. The Kiligwa, 

&ma9 and Ipmvik Mvers were intersected during the float9 with th~ 

trip ternhating at the confluence of the Etivluk River* 

The survey was accaqlished in faur days in a 12-foot Avon raft 

with a four horsepower9 short-shaft outboard motor. The rafe was 

sufficiently large to carry the two person party, food9 fuel, camping, 

and depth sounding equipmeate The outboard was only useful in the long 

river pods of slow moving water and had to be lifted for must riffles* 

Infrequently a riffle was shallow enough to require lining the raft 

across the rocks without passengers aboarda 

A Hodel 206 Ranger Eelicopter deposited us and gear approximately 

ten river niLes above the confluence of he Kiligwa River on the 

afzemoon of 26 July l979e Ve were et by helicopter at the designated 

termination pobt at noon on the 30th of July at the confluence of the 

Etivluk and Colville Rivers. Progress dong the river ranged from Za3 

to !5*8 kilomete~s per hour ~5th an average of 3-3 km/hra This a-verage 

was fairly high cansidering it included all stops other than for making 

evening camp. There were nu major mechanicd problems and minbal 

sampling was done along the way* Slow progress was made early in the 

fhat trip due to little use of the outboard mutor and frequent stops 

to hike along bluffs for raptor nest surveys. Progress was made at 

approximately 5*8 kilometers per hour during the very last day af the 

float when almost no staps were made because bluffs and nests were 

infrequent and the outboard mutor was used as often as water depth 

pemitted* Therefore3 the speed or progress made on this last day was 

excepti~nally good and should not be considered the average. Progress 

of about 15-20 kilometers per day is reasunable under similar circmscances9 if some data acquistiort is to be accomplished along the way. 

A Lowrance Madel LRG-1510 portable, recording fathometer was 

installed on the raft with a 12 volt battery for power- The fathometer 
record could be annotated to reference record number, the, river 

location, or other observations necessary for later data reduction* 

The depth record accuracy was better than O=l meter. The fathometer 

depths had to be referenced to locations along the river to quantify 

river distance with a particular depth range* Depth ranges were easily 

tdentified on the fathometer record, but rigorous annotation and 

analysis were necessary to associate the depth ranges with lacatious - - - and distances surveyed on the river* A caucerted effort was made to 

standardize and maintain consistent fathometer record chart speed and 

down river raft v~l~city to simplify depth record/river distance and 

lacation interpretation* The slowest possible fathometer record chart 

spec$ was used thoughout the entire survey. The raft velocity was 

maintained by notoring through the long slow moving pools at about the 

same speed encountered without the outboard motor i.12 the riffles and 

faster moving water between the deep pools. Although this was not an 

exact method, the cross checks on photographs and maps indicate that 

the precisian was sufficient for the ensuing analysis* 

For the purpose of data analysis* the Colville Survey was divided 

ineo three sections. During the first two sections, fathometer records 

were made intermittently9 prixarily of deep ziver charnele A continuous 

fathometer tracing was obtained of the last forty-nine kilometers of 

the sumey. 

Color infrared (CIR) aerial photographs it 1:60,000 scale and USGS 

l:25O9Of30 scale map8 were used to keep track of fathometer record start 

and stop points and other observaticms during progress along the river. 

The 1:603000 aerial photographs were absolutely essential for the type 

of survey undertaken. The phot~grapb were stereo pairs covering the 

entixe Colville RLver area floatede A small pocket stereo viewer was 

used to prevLew relief features encountered. The photographs also 

provided some preview of river channel chara~teristtcs~ The most active 

river channel could be selected from the photographs, and changes in 

channel depths and direction could be anticipated* The photographs 

were of sufficient quality that changes in water color were used to 

predetermine riffles and in same cases ta lacate deep water within a 

large river pool* Therefore, the aerial photographs provided a valuable aid in river navigation for selection of a course that would 

provide fathometer records to best delinate maximum river channel 

depths in the nost active river channel. 
Figure 2- Illustration of raft navigation used to record depth and method used 

to interpret distances of river channel at or below 2 ad 3 meters. 

~TQO~ a- Colviilo River pool with axis of deep ehannsi (a---_) and k,Â¥-rpath of raft (transect,-) defined. 

[~ottom] b- Depth from fathometer record relative to above transects 

and the resulting interpretation of channel distances at 22 ond 23 

meters. 
Figure 3. Illustration of fat hornet er record analysis /interpretation for riffles. 
- -- 

The deepest portion of a river channelcannot be defined with a 

single downriver transect, therefore, the main channel was navigated in 

an effort to best define the greatest depths in the axis of the channel. 

The raft and fathometer could not be kept over the deepest portion of 

the channel at all times, but was angled sli htly across the channel 

until the channel axis was crossed and the river began to shoal. The 

raft was then turned toward the opposite shore to again recross the 

channel axis (Pig. 2a). Careful attention to the fathometer record 

depth changes and coordination with river course for best raft navigation provided a continuous series of down river transects that repeatedly crossed the main channel axis. These transects were used coileclively to define river channel axis depth with careful analysis and 

interpretation, (Fig. 2b). 

Maximum depths along the fathometer tracing showed where the. 

transect intersected the main channel axis. Measuring between the 

point where a 2 meter depth was first encountered and where i 

encountered along the transect of a pool provided a conservative 

estimate of distance which is at or below 2 meterse Sections of the 

river at or below 3 meters were similarly calculated. 

Riffles were measured in a similar manner. A riffle was defined 

specifically for this study to accommodate the peculiarities of the 

fathometer record. The beginning and termination points of a riffle 

were chosen to be .3 meter on the fathometer recordo However, as long 

as the record did not indicate water depths e 

the .3 meter end points, the riffle was cons 

These riffles were characteristically fast moving water, usually choppy 

over large cobbles or small holders, in the stretches of river 

separating the large deep river pools. 

Percentages were calculated of river distance with water depth 

range in the following categories: riffle, >2m, and >3m0 The fathometer data for the last 49 kilometers of survey (Section 3) was most 

important because it was continuous data. The deep water habitat 

(i.e., + and >3m) was plotted on both 1:60,000 aerial photographs and 

a DSGS 1 : 250,000 map. 

Stereopairs of the aerial photographs were used to locate bluffs 

that intersected or were immediately adjacent to the river water' s edge 

from which fathometer records were obtained. The focus was on those 

bluffs that were part of the riverbank or contributed sufficiently to 

the active channel course to be considered the causal factor contributing to the existing river channel morphology. Bluffs affect the 

river channel when they or the rubble from them restrict the river 

channel course. 
A 1:250,000 scale map depicting deep water areas along the last 49 

kilometers of the Colville Survey was compared with 1:250,000 scale 

Side Looking Airborne Radar (SLAR) imagery of the same Colville River 

area to see if any water depth/SLAR image correlation was evident. I 

hypothesized that bright SLAR images from the ice-covered Colville 

might occur at deep river locations where liquid water beneath the ice 

was assured. This SLAR image phenomenon has been documented for arctic 

lakes and in the Mackenzie River Delta (Campbell et al., 1975). 

RESULTS AMD DISCUSSION 

Figure 4 shows the location of deep water areas (>2m and 23) 

found along the three sections of the Colville River. Depicted on a 

1:250,000 scale map, the data show deep pools surveyed in each section: 

6 deep water areas were surveyed in Section 1, 9 deep water areas were 

surveyed in section 2 and 41 deep water areas were found with continuous survey in Section 3. Bluffs that occur as riverbanks along 

navigated river channels are also shown in Figure 4. The relationship 

between bluffs and deep water habitat is evident and is discussed later. 

The water depth data is summarized in Table 1 fx the sections of 

the entire 152 kilometer survey. The data in Section 3, the last 49 

kilometers of the trip, are most significant in that the fathometer 

depths were continuously recorded for both deep and shallow areas of the 

river channel. 

The maximum depths of the deep channels recorded ranged from 1.5 

to 7.0 meters. The 7.0 meter depth was recorded while rafting Section 

1 near the starting point. This upper section of river did not have as 

much water as it was prior to the confluence of the Kiligwa and Kuna 

Rivers, but it had larger bluffs with deep cut river channels adjacent 

to the bluffs. The maximum pool depth found in the last 49 kilometers, 

Section 3, was only 4.9 meters. The bluffs in this area were less 

frequent and appear to have less significant impact on the river 

channel course than those upriver in Sections 1 and 2. The average 

maximum pool depth for the entire area floated was 3.6 meters. An ice 

cover of 2 meters would still leave 1.6 meters of water beneath the ice 

for overwintering fish. 

Table 1 also lists percentages of shallow versus deep water 

habitat calculated from the 49 kilometers of continuous fathometer 

records acquired throughout Section 3 of the survey. Twenty-three 

percent of this portion of the river was riffle or shoal where even a 

short shaft four horsepower outboard motor had to be lifted clear of 

the water to avoid propeller damage. Twenty percent was 22 meters, 

while only 4.6 percent as 23 meters in depth. This meant that in 

Section 3 only about one fourth of an area >2m had depths 33x11. In 

Section 1 and 2 close to one half of the area within a pooi>3m was 
a) Section 1. 51.5 krn of river rafqd with infrequent fathometer records of 

wcter dest!'l taken only in areas with obvious dsep 

river channel. 

27 July 

2230 ADT 

26 July '*' 

1400 ADT 

158" 32' W. Long. ^-?"s I 

Long. 

b Section 2. 51.5 km of river rotted with fathometer records 

taken only in, but the majority of, the areas 

with obvious deep river channel. 

29 July 

157' 36' W. Long. 

T 

w. Long* 

C) Section 3. 49 km of river rafted with 

50 July 

1230 A?T 

155' 58 W Long. 

29 July 

1045 ADT 

156' 46' W. Long. 

l a = bluff 

= 23me~ers 

kale 1.250,000 

Figure 4. 0.b.e. Colville River Float depicted 3 contiguous sections with 

deep water channels, river bluffs, and major tributaries 

annotated. 9 
Ã *,Ã it- 

=Laa w-. CM WID 

(U ar-4 
-- 

- >3m deep. Shallow areas with water dept-heilightly greater than a 

riffle yet less than 2 meters were not described in Table 1. However, 

this is the remaining percentage of the river excluding riffles and 22 

meter areas. In Section 3, 57 percent of the river channel water depth 

was slightly greater than riffles yet less than 2 meters. 

The 1: 60,000 scale color infrared (CIR) photographs were essential 

for performing this study as previously discussed. Interpretation and 

analysis of river channel depths on the fathometer record were enhanced 

by the use of the aerial photographs. River pools with the deep 

channels could be differentiated from the narrower riffles with light 

colored shallow and/or choppy water. Some of the photograph characteristics that aided in placement of deep versus shoal areas were subtle 

or inconsistent (i.eo, color of water, width and shape of river, 

presence or absence of river bars, and confluence of other water, sources) 

while bluffs were obvious and a consistent indicator of deep water. 

Unfortunately, the photographs are too extensive to include in this 

report. 

During the float, fathometer records were taken adjacent to 15 

river bluffs. Table 2 shows the relationship between bluffs and deep 

water areas. Deep water channels were found off every bluff surveyed 

along the 152 kilometer survey. Of the 56 deep water (>2m) areas 

defined by fathometer records, 18 were associated with one of these 

bluffs. Therefore, 32 percent of the deep pools surveyed were associated 

with a river bluffÃ Only 20 percent of the deep pools were associated 

with bluffs in Section 3 (Table Z), but the bluffs were less frequent 

in this river section (Fig. 4). Every one (100 percent) of the 15 

river bluffs surveyed had at least one deep (>2m) river channel area 

adjacent Co it. Sixty-nine percent of these had water depths 23 meters. 

This association of bluffs with deep water areas has practical application. Stereopairs of the aerial photographs can be used for other 

areas of the river to find bluffs where deep water river habitat can be 

predicated to be present with reasonable confidence. Some care and 

judgment must be used to apply this indicator along the entire river. 

The following river and buff conditions effect the occurrence of deep 

water at bluffs: river gradient; bluff/river flow association; suspended 

sediment load; and bluff morphology and composition. When an active 

river channel is restricted by a resistant bluff face, river channel 

scouring results. The data in Figure 4 and Table 2 substantiate the 

resulting association of deeply scoured river channels adjacent to the 

bluffs surveyed; 

Although the aerial photographs utilized were two years old (NASA, 

July 1977), the active river channel and bars observed appeared to be 

much the same configuration in the photographs as observed during the 

float trip in July 1979. During the 152 kilometers (ten) of the river 

traversed, only two locations were observed where the main channel had 

changed. It had returned to a preexisting channel that had not been as 
m 

'ST 
active in July 1977. These two changes amounted to approximately 3 km 

of the 152 km floated. This is less than 2 percent change in river 

course for the two year period. We accomplished some ground verification 

of color changes noted in aerial photographs of gravel bars. The size 

and shape of river bars, as well as, pockets of sorted sand and gravel 

materials, within large river bars, were similar to those noted in the 

two year old photographs. The CIR aerial photographs also delineated 

existing river bar willow areaswith very good clarity. 

Section 3 of the Colville River (Fig. 4c) was imaged with SLAR 

five different times while ice-covered this past winter and once when 

ice-free this simmer. Part of the purpose of this study was to determine 

if any correlation exists between deep water areas delineated in Figure 

4c at 1:250,000 scale and the varying signal returns discernible on the 

1:250,000 scale SLAR imagery. No significant correlation was found 

between the two. Freshwater arctic lakes not frozen to the bottom 

provide a high SLAB. signal return delineating the zone of ice contact 

with the lake bottom (Weeks et al., 1978). Some plausible reasons for 

a bright return from lakes not yet frozen to the bottom versus no such 

differentiatable SLAR return from a river not frozen to the bottom are 

discussed below, but need additional research for verification. 

Colville River pool morphology, bottom material, pool size, and ice 

cover are physically different from that of lakes with the bright SLAR 

images. The river areas with liquid water beneath the ice are close to 

the minimum mapable unit for SLAiL The river bottom is composed of 

rock and gravel rather than the fine sand, silt, and organics found in 

the lakes. River ice forms from moving water unlike lake ice which 

forms from a stagnant body of water., The ice crystals (i.e., orientation 

and size) that form under these two different conditions are likely to 

be different. 

Gas bubbles within river and lake ice were observed to be different. 

The gas bubble content of Colvilie Elver ice was checked within Section 

3 on 26 November 1979. The river ice did not have the elongate, 

vertically oriented gas bubbles so common in all freshwater lake ice 

samples observed by the author over the past year. The differences in 

gas bubbles may be a significant factor in returning the SLAR signal, 

but additional work on all the above and possibly other parameters is 

necessary before any conclusion can be reached. 

Unvegetated river bars are difficult to distinguish from river 

channels on the winter SIAR imagery. Summer imagery, when the river is 

ice-free, is best for differentiating the river bar from river channel. 

Some of the river bars had high signal returns which were very bright 

on the winter imagery. These were found to be feltleaf willowp Sdix 

alaxensis, which matched willow stands on the summer CIR photography. 

The willows could easily be distinguished from unvegetated river bar 

and ice-covered river channel on the STAR Images. The high return from 

these willows seems to be due to fall and winter retention of dead . 
leaves on the willow branches. Willow leaves in the Section 3 area of 

the Colville were observed on 26 November 1979 to be dry, curled, and 

strongly attached to the stems. The curled leaves had dimensions of 

about 2-3cm width and 4-6cm length. These leaves, at or near the SLAB. 

signal wave length (3ca), seem to reflect a high percentage of the 

signal, thus defining the willow stands on winter imagery. June and 

August imagery did not delineate willow areas nearly so well as did 

December, February, or April imagery. The willow leaves are probably 

shed during the late winter or early spring. The new, live and growing 

leaves seem to reflect less SLAR signal, than do the dry curled ones. 

SLAR imagery from anytime of year is useful for depicting bluff 

and other relief features. However, the SLAB. flight direction relative 

to the direction of the bluff face must be taken into consideration as 

all the bluffs are not imaged equally well. The bluff faces parallel 

to or facing away from the radar signal will not be imaged nearly so 

well as those facing the radar signal. 

The 1:250,000 scale SLAR is too small to provide the resolution 

necessary for discrimination of detailed riverine habitat. Even the 

1:60,000 CIS. aerial photographs are inadequate for detailed riverine 

habitat studies, but proved to have adequate detail and be essential 

auxiliary data for this study. 

Some angling was done during the four day float trip. Most of 

the fishing effort was unrewarded. Most fishing was done at the 

confluence of creeks and rivers or near deep channels encountered. 

Only one grayling 38 cm long was taken from the Colville during this 

raft trip. This one was taken at the confluence of the Kiligwa River. 

Several grayling were caught in the Ipnavik River within a mile of its 

confluence with the Colville River. Suspended sediment load in the 

Colville River water was fairly low during the raft trip.. The river 

bottom could be seen through up to 1.5 to 2.0 meters of water. 

SUMMARY 

River channel water depths were surveyed in the Upper Colville 

River. Twenty three percent of the river was riffle. Fifty seven 

percent of the river channel length was of intermediate depth between 

riffle and 2 meters. Twenty percent was greater than or equal to 2 

meters in depth, while only 4.6 percent of the channel was greater than 

or equal to 3 meters in depth. Deep water (>2m) existed adjacent to 

every bluff surveyed on the river. The maximum water depth recorded 

was 7 meters. An average maximua channel depth of 3.6 meters was 

calculated . 

Aerial photography at 1:60,000 scale of the river was an invaluable 

aid in this survey. SLAB. imagery at 1:250,000 scale of the same area 

was found to be of little or no value for delineating deep river channel 

areas. 
Campbell, WoJo, ROO. Raaiseier, WÃ§F Weeks, and Po Gloersen. 1975. 

rated approach to the remote sensing of floating icee I& 

ngs of the Third Canadian Symposium on Remote Sensing, 

, Alberta, 22-24 Sept. 1975, p. 445-487, 

Reynolds, PeE. 1980. Raptor surveys in southeastern MPR-A, 1978-1979. -- 

Bureau of Land Management, NPR-A Report, Fairbanks, Alaska. 

Weeks, W.FÃ§ A.G. Fountain, M.L. Bryan and C. Elachi, 1978. Differences 

in radar return from ice covered lakes. J. Geophysical Res*, Val. 

83, No. C8. pp. 4069-4073. 
OPEN FILE REPORTS 

The category of "open File ~eport" is used by Bm-Alaska to identify the 

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Copies of open file reports are also available for inspection at the USDI 

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Center library.