Future Data Improvements
None planned.
Instream Spawning and Rearing Habitat
Data Source: ARWA 2017 (pgs. 91-107) and USFWS 1985 (pgs. 10-11)
The instream spawning habitat for Fall Run Chinook Salmon and Steelhead in the American River is based on a spawning habitat suitability and availability analysis performed by the Sacramento Water Forum. The Water Forum conducted the analysis as part of the Lower American River Biological Rationale Development and Performance of the Modified Flow Standard (ARWA 2017). The instream juvenile rearing habitat for Fall Run Chinook Salmon is from instream flow studies conducted by Mark Gard from the California Department of Fish and Wildlife. These analyses uncovered relationships between flow and both suitable spawning habitat and suitable rearing habitat for the Lower American River. Cells A35:D46 in the ‘American’ tab of the IFIMWUA spreadsheet contain sums of the instream flow evaluation values from reaches Sailor Bar, Ancil Hoffman, Watt, and H Street. These values were equally weighted to obtain composite instream rearing weighted usable area (WUA) values in square feet per 1000 feet of river.
Spawning Data
| flow_cfs | FR_spawn_wua | ST_spawn_wua | watershed |
|---|---|---|---|
| 0 | 0.00 | 0.00 | American River |
| 50 | 13209.35 | 11331.81 | American River |
| 100 | 25142.28 | 21600.69 | American River |
| 150 | 35890.51 | 30879.70 | American River |
| 200 | 45542.15 | 39238.99 | American River |
…with 40 more rows.
Rearing Data
| flow_cfs | FR_fry_wua | FR_juv_wua | watershed |
|---|---|---|---|
| 300 | 59897.00 | 112381.25 | American River |
| 500 | 54065.00 | 108736.25 | American River |
| 750 | 49959.25 | 99007.00 | American River |
| 1000 | 42334.00 | 93968.25 | American River |
| 1250 | 38006.00 | 86484.75 | American River |
…with 6 more rows.
Spawning WUA
The Fall Run Chinook Salmon and Steelhead spawning habitat data from ARWA 2017 is located in Attachment B. Fall Run Chinook Salmon data are in Table B-4 on page 91 and Figure B-8 on page 92. Steelhead data are in Table B-9 and Figure B-26 on page 107.
The following plot shows the composite WUA in square feet per thousand feet for Fall Run Chinook Salmon and Steelhead. The WUA values combine data from all evaluation reaches. These area per length rates are multiplied by the total spawning reach length mapped by the SIT to estimate areas of habitat. 
Rearing WUA
The following plot shows the rearing WUA in square feet per thousand feet for fry and juvenile Fall Run Chinook Salmon. These rates are multiplied by the total rearing reach length mapped by the SIT to estimate habitat area. 
Floodplain Rearing Habitat
Data Source: Central Valley Floodplain Evaluation and Delineation (CVFED) HEC-RAS hydraulic model
The entire mapped rearing extent of 22.8 miles was modeled using Central Valley Floodplain Evaluation and Delineation (CVFED) HEC-RAS hydraulic model. An active channel area of 670.2 acres, estimated through remote sensing analysis, was subtracted from total inundated area to obtain inundated floodplain area.
Floodplain Data
The areas represent total inundated area in acres.
| flow_cfs | FR_floodplain_acres | ST_floodplain_acres | watershed |
|---|---|---|---|
| 1200 | 0.00 | 0.00 | American River |
| 2200 | 6.00 | 6.00 | American River |
| 3200 | 159.88 | 159.88 | American River |
| 4200 | 228.01 | 228.01 | American River |
| 5200 | 268.53 | 268.53 | American River |
…with 29 more rows
Floodplain Plot
