STREAM INVENTORY REPORT
TWO LOG CREEK (Upper Section)
Two Log Creek is a tributary to the Big River. Elevations range from 0 feet at the mouth of the creek to 600 feet in the headwater areas. Two Log Creek’s legal description at the confluence with the Big River is T17N R16W Sec22. Its location is 39°19'13"N. latitude and 123°36'37"W. longitude according to the USGS Comptche 7.5 minute quadrangle.
HABITAT INVENTORY RESULTS
The habitat inventory of June 20, 1996 through June 24, 1996, was conducted by Diana Hines and Dave Wright. The total length of surveyed stream in Two Log Creek was 10,243 feet (1.9 miles, 3.04 KM) (Table 1). There were no side channels in this section of creek. Flow measured at the mouth of Two Log Creek on 6/18/96 was .119 cubic feet per second (cfs).
Two Log Creek consisted of two reaches: B3 for the first 9,182 feet and B4 for the remaining 1,061 feet.
Table 1 summarizes the Level II Riffle, Flatwater and Pool Habitat Types. By percent occurrence Riffles comprised 16%, Flatwater 25% and Pools 59% of the habitat types (Graph 1). By percent total length, Riffles comprised 7%, Flatwater 33% and Pools 60% (Graph 2).
Fourteen Level IV Habitat Types were identified and are summarized in Table 2. The most frequently occurring habitat types were Mid Channel Pools 28% and Low Gradient Riffles, Step Runs and Corner Pools all at 11% each (Graph 3). The most prevalent habitat types by percent total length were Mid Channel Pools at 27%, Step Runs 21% and Corner Pools 13% (Table 2).
Table 3 summarizes Main, Scour and Backwater pools which are Level III Pool Habitat Types. Main pools were most often encountered at 49% occurrence and comprised 46% of the total length of pools.
Table 4 is a summary of maximum pool depths by Level IV Pool Habitat Types. Pools with depths of two feet (.61 m) or greater are considered optimal for fish habitat. In Two Log Creek, 64 of the 161 pools (40%) had a depth of two feet or greater (Graph 4).
The depth of cobble embeddedness was estimated at pool tail-outs. Of the pool tail-outs measured, 0% had a value of 1, 1% had a value of 2, 5% had a value of 3 and 94% had a value of 4 (Graph 5).
Of the Level II Habitat Types, Pools had the highest mean shelter rating at 64 (Table 1). Of the Level III Pool Habitat Types, Main Pools had the highest mean shelter rating at 120 (Table 3).
Of the 161 pools, 9% were formed by Large Woody Debris: .6% by logs and 8.4% by root wads (calculated from Table 4).
Table 6 summarizes dominant substrate by Level IV Habitat Types. Of the Low Gradient Riffles fully measured, 67% had gravel as the dominant substrate (Graph 6).
Mean percent closed canopy was 90%: 48% coniferous trees and 42% deciduous trees. Mean percent open canopy was 10% (Graph 7, calculated from Table 7).
Table 7 summarizes the mean percent substrate/vegetation types found along the banks of the stream. Mean percent right bank vegetated was 63% while mean percent left bank vegetated was 64%. Coniferous trees were the dominant bank vegetation type in 60% of the units fully measured. The dominant substrate composing the structure of the stream banks was Sand/Silt/Clay, found in 88% of the units fully measured.
The information gathered in the process of habitat typing will provide Georgia-Pacific with baseline data on the current condition of this creek and the available habitat for salmonids. This data will then be used to identify components of the habitat which are in need of enhancement so that the appropriate conditions for Two Log Creek can be improved.
According to Flosi and Reynolds (1994), a stream with 50% of its total habitat comprised of primary pools is generally desirable. Primary pools are at least two feet deep in first and second order streams and at least three feet deep in third order streams. The information from Graph 4 on maximum depth in pools was used to determine percent of primary pools. Two Log Creek, a first order stream, is comprised mainly of shallow pools with only 40% of the pools having a maximum depth of two feet or greater.
Large Woody Debris
The presence of Large Woody Debris (LWD) in streams is a significant component of fish habitat. Woody debris creates areas of low flow, providing a refuge for fish during periods of high flow (Robison and Beschta, 1990). Woody debris also provides cover for fish, lowering the risk of predation. The percent of pools in Two Log Creek formed by LWD was 9%. Whether these numbers are high or low, relative to the needs of salmonids is difficult to ascertain since the optimum amount of woody debris in streams has not been specified (Robison and Beschta 1990). It is interesting to note, however, that coho were found in stream reaches of the Ten Mile River Basin where approximately 50% of pools were formed by large woody debris. Those reaches that did not support coho had a significantly lower percentage of pools formed by large woody debris (Ambrose et al, 1996).
There are two important benefits of canopy cover in coastal streams. Canopy keeps stream temperatures cool as well as providing nutrients in the form of leaf litter and organic material (Bilby 1988). Mean percent canopy cover for the Two Log Creek was 90%. This is relatively high since a canopy cover of 80% or higher is considered optimum, Flosi and Reynolds (1994).
Since salmon generally create redds at the heads of riffles we were mainly concerned with the dominant substrate in these units. In Two Log Creek, 67% of the Low Gradient Riffles had gravel as the dominant substrate. The relatively high presence of gravel in riffles indicates that there is a sufficient amount of substrate available as potential spawning habitat in this creek.
The high embeddedness values found throughout Two Log Creek could hinder the survival of the eggs deposited in the redds. High silt levels reduce water circulation within the substrate, thus lowering the oxygen levels needed by salmonid eggs (Sandercock, 1991).
Substrate embedded with silt in varying degrees were given corresponding values as follows: 0-25%= value 1, 26 - 50% = value 2, 51 - 75% = value 3 and 76 - 100% = value 4. According to Flosi and Reynolds (1994), creeks with embeddedness values of two or higher are considered to have poor quality fish habitat. In the Two Log Creek, 100% of the pool tail-outs measured had embeddedness values of two or more.
It is important to consider, however, that the above embeddedness values were obtained in the summer during low flow conditions. In winter and spring, flows are usually higher due to the rainy season and the lowered evapotranspiration of the trees. This higher flow probably carries away much of the silt previously deposited. Since spawning usually occurs during the winter, the substrate may not be as embedded as in the summer.
Overall, Two Log Creek appears to have sufficient substrate for spawning as well as sufficient canopy. This creek also appears to have high embeddedness values and consist of a relatively low percentage of primary and LWD formed pools.
Georgia-Pacific will attempt to maintain a healthy environment for salmonids in this creek through sound management practices and restoration and enhancement projects.
Two Log Creek should be managed as an anadromous, natural production watershed.
Where feasible, design and engineer pool enhancement structures to increase the depths of pools. This must be done where banks are stable or in conjunction with stream bank armor to prevent erosion.
Increase percent of pools formed by large woody debris by recruiting more large woody debris into the creek.
Inventory and map sources of stream bank erosion and prioritize them according to present and potential sediment yield. Identified sites should then be treated to reduce the amount of fine sediment entering the watershed. In addition, sediment sources related to road systems need to be identified, mapped and treated according to their potential for sediment yield to the watershed.
Log debris accumulations retaining large quantities of fine sediment should be modified carefully, over time, to avoid excessive sediment loading in downstream reaches.
The following memos were taken in the field at the time of survey. All distances are approximate and measured in feet from the confluence.
768 approximately 6 young of year (yoy) observed
1061 hobo temp pool (1061' from confluence). yoy observed
1232 yoy observed
1345 yoy observed
1940 yoy observed
2218 yoy observed
2657 4 yoy coho, 1 yoy steel head
2846 yoy observed
3465 tributary entering left bank at end of unit
3686 undercut bank along left bank approximately 4 ft long
4039 tributary entering right bank at 36'
4232 yoy observed
4818 4 yoy observed, 4 coho
5672 tributary entering right bank at 90'. channel type changes to B3
6138 yoy observed
6168 bank failure on left bank 15' x 30l contributing gravel and sand
6280 log jam along left bank 6'h x 12'w x 6'l lwd and swd
6451 approximately 10 yoy observed (at least 4 were coho). log jam over pool 10'h x 18'w x 12'l, mostly lwd
6471 bank failure on right bank 20'h x 25'l contributing fines
6583 log jam over beginning of riffle 8'h x 12'w x 10'l, includes large root wad and lwd
7280 tributary entering left bank at beginning of unit
8140 tributary entering right bank at 10' into unit
8432 yoy observed
8839 yoy observed
9098 3 inch sthd
9197 yoy observed
9616 tributary entering right bank at end of this unit
9711 bank failure along left bank 25'l x 15'h contributing fines
9901 yoy observed
9993 bridge crossing at end of pool
10522 root mass provides approximately 3' of undercut cover
10694 pool has approximately 3' of undercut bank along left bank
11065 bridge crossing over creek at end of this unit
11732 approximately 2' undercut bank along either side
11815 tributary entering left bank at 40'
11916 yoy observed
12004 2' of undercut bank along right bank. 3 inch salmonids observed
12049 2' of undercut bank along left bank
12088 2 yoy coho observed
12339 yoy observed
12534 3' undercut bank along left bank
12599 2' undercut bank along left bank
12767 3 inch salmonids observed
12990 yoy observed
13259 2 coho observed
13399 tributary entering left bank at end of unit
13485 yoy observed
13658 3 large redwood logs across creek
14301 tributary entering right bank at end of pool
14352 yoy observed
14695 channel type changes to B4
15218 log jam over creek 8'h x 2'w x 10'l swd and lwd
15571 log jam over creek 10'h x 20'l x 15'w. creek turns into a marsh after this unit. marsh is approximately 123'l x 30'w. yoy observed in marsh. we were unable to walk through marsh, we walked around and re-entered at other end.
15588 unit goes through marsh. after this unit marsh becomes overgrown with blackberry bushes and we have to walk .2 miles around before marsh ends and we are able to re-enter the creek.
15600 yoy observed
15809 log jam over creek 40'l x 12'w x 10'h
16009 End of survey. property line ends here. tributary enters from right bank through culvert. approximately 3'h drop to surface of water, could be a fish barrier. mainstem of creek continues but becomes gradually smaller. habitat diminishes about 200' further. water is barely flowing, creek is highly embedded.