Future Data Improvements
None planned.
Instream Spawning and Rearing Habitat
Data Source: CDFW 1979 (pgs 11-15) and UFWS 2013 (pgs 46-47)
The instream spawning area for Fall Run Chinook Salmon in Cottonwood Creek is based on data from a collaborative study in 1979 by the U.S. Army Corps of Engineers and the California Department of Fish and Wildlife. The federal instream flow method was used to measure the rearing habitat at three reaches, that together span a 22.4 mile stretch of Cottonwood Creek. Spawning habitat data were provided on pages 11-15 (Table 1 and Table 5) of the CDFW 1979 report. Instream rearing habitat for Fall Run Chinook Salmon and Steelhead are based on the UFWS 2013 study that included 26 habitat transects on lower Cottonwood Creek. The habitat data from this study are on pages 46 and 47 of the USFWS 2014 report. The instream spawning and rearing habitat data were provided to us by Mark Gard from the California Department of Fish and Wildlife.
Spawning and Rearing Data
The instream spawning and rearing habitat data described above for Fall Run Chinook Salmon (FR) is combined for use in the Decision Support Model (DSM) in the following format. Units are in square feet per 1000 feet.
| flow_cfs | FR_spawn_wua | FR_fry_wua | FR_juv_wua | ST_fry_wua | ST_juv_wua | watershed |
|---|---|---|---|---|---|---|
| 15 | NA | 8143.185 | 2772.537 | 1620.655 | 596.0895 | Cottonwood Creek |
| 21 | 198.4196 | NA | NA | NA | NA | Cottonwood Creek |
| 37 | 233.6790 | NA | NA | NA | NA | Cottonwood Creek |
| 52 | 260.4626 | NA | NA | NA | NA | Cottonwood Creek |
| 71 | 269.6165 | NA | NA | NA | NA | Cottonwood Creek |
… with 21 more rows
Spawning WUA
The following plot shows the weighted usable spawning area (WUA) in square feet per thousand feet for Fall Run Chinook Salmon. These area per length rates are multiplied by the total spawning reach length mapped by the Science Integration Team (SIT) to estimate available habitat. 
Rearing WUA
The following plot shows the rearing WUA in square feet per thousand feet for Fall Run Chinook Salmon and Steelhead fry and juvenile. These rates are multiplied by the total rearing reach length mapped by the SIT to estimate available habitat. 
Floodplain Rearing Habitat
Data Source: USFWS / FEMA 1D HEC-RAS hydraulic model
Fall Run
A 22.4 mile portion of the entire mapped rearing extent of 22.4 miles was modeled using USFWS / FEMA 1D HEC-RAS hydraulic model. Of the entire mapped rearing extent, 22.4 miles were classified as low gradient and 0 miles were classified as high gradient based on a geomorphic analysis of long profile slopes and valley widths. The floodplain area per unit length was determined for the modeled extent and used to approximate areas for the non-modeled extent. The area per unit length was scaled by a factor of 0.1 for the high gradient extent. There was no scaling factor applied to the low gradient extent.
Spring Run
A 22.4 mile portion of the entire mapped rearing extent of 119.5 miles was modeled using USFWS / FEMA 1D HEC-RAS hydraulic model. Of the entire mapped rearing extent, 22.4 miles were classified as low gradient and 97.1 miles were classified as high gradient based on a geomorphic analysis of long profile slopes and valley widths. The floodplain area per unit length was determined for the modeled extent and used to approximate areas for the non-modeled extent. The area per unit length was scaled by a factor of 0.1 for the high gradient extent. There was no scaling factor applied to the low gradient extent.
Steelhead
A 22.4 mile portion of the entire mapped rearing extent of 142.3 miles was modeled using USFWS / FEMA 1D HEC-RAS hydraulic model. Of the entire mapped rearing extent, 22.4 miles were classified as low gradient and 119.9 miles were classified as high gradient based on a geomorphic analysis of long profile slopes and valley widths. The floodplain area per unit length was determined for the modeled extent and used to approximate areas for the non-modeled extent. The area per unit length was scaled by a factor of 0.1 for the high gradient extent. There was no scaling factor applied to the low gradient extent.
Floodplain Data
The areas represent total inundated area in acres.
| flow_cfs | FR_floodplain_acres | SR_floodplain_acres | ST_floodplain_acres | watershed |
|---|---|---|---|---|
| 40 | 0.00 | 0.00 | 0.00 | Cottonwood Creek |
| 400 | 7.81 | 11.21 | 12.01 | Cottonwood Creek |
| 760 | 13.46 | 19.31 | 20.68 | Cottonwood Creek |
| 1120 | 21.57 | 30.94 | 33.14 | Cottonwood Creek |
| 1480 | 28.45 | 40.81 | 43.71 | Cottonwood Creek |
… with 27 more rows
Floodplain Plot
