Elephant Habitat Modeling Details

Overview

Habitat and flow commitments made under the Healthy Rivers and Landscapes (HRL) program were included as inputs to the R2R modeling framework for the following watersheds:

• American River

• Feather River

• Mokelumne River

• Yuba River

• Tuolumne River

Staff from the Tuolumne River and Yuba River provided flow-to-suitable area relationships representing anticipated effects of the HRL commitments. These watersheds developed methodology to scale existing flow-to-suitable habitat relationships based on existing and proposed habitat projects. Documentation for the Tuolumne River methodology is available here and for the Yuba River methodology here.

For the Mokelumne, American, and Feather Rivers, R2R used the flow-to-suitable area relationships provided for the Scientific Basis Report (SBR), Section 6 to ensure consistency across the basin.

Methods

The following workflow was used to incorporate these relationships into the R2R habitat model framework:

1. Read in the flow-to-suitable area relationship used in the SBR.

2. Functionalize the relationship using interpolation with flow as the predictive variable and suitable habitat as the response variable.

3. Generate estimated habitat using flows from the HRL CalSim3 run for the model years (1980-2000).

Read and functionalize flow-to-area curves

American River

HRL flow-to-habitat relationship

Instream and floodplain rearing habitat were provided. They are the same as those used in the SBR.

Data Source: FlowWest coordinated with representatives for the American River to determine the best scientific information available to quantify existing suitable habitat, and to describe the VA non-flow habitat as suitable area that varies with flow. Habitat data were provided to R2R for use in accounting for planned habitat projects by Erica Bishop and Chris Hammersmark. Data provided represented the HRL commitments based on flow-to-habitat relationships borne out by recent EIP designs and constructed projects for the subject habitat type.

Watershed	Flow (cfs)	VA juvenile habitat (acres)
American River	500	20
American River	800	30
American River	2000	40
American River	3500	50
American River	5500	65
American River	7500	55

Feather River

HRL flow-to-habitat relationship

Spawning and instream rearing actions are only for the LFC.

Data Source: Data came from the FERC relicensing spawning WUA/RSI and were provided for the SBR by Jason Kindopp.

Watershed	Location	Scenario	Flow (cfs)	Habitat type	Suitable acres
Feather River	LFC	Existing	150	Spawning	3.36
Feather River	LFC	Existing	200	Spawning	5.72
Feather River	LFC	Existing	250	Spawning	8.31
Feather River	LFC	Existing	300	Spawning	10.86
Feather River	LFC	Existing	350	Spawning	13.28
Feather River	LFC	Existing	400	Spawning	15.49

Mokelumne River

HRL flow-to-habitat relationship

Instream and floodplain rearing habitat were provided. They are the same as those used in the SBR.

Data Source: Data were provided by Robyn Bilski for the SBR.

Flow (cfs)	Habitat type	Suitable acres	Scenario
105	Spawning	8	HRL
105	Juvenile	209	HRL
105	Fry	189	HRL
140	Spawning	10	HRL
140	Juvenile	202	HRL
140	Fry	179	HRL

Generate estimated habitat using flow

Habitat is generated using the functionalized flow-to-area curves. Flow inputs are provided by a CalSim3 LTO_12a run, which incorporates some HRL flow commitments. The plot below shows an example comparison of juvenile and floodplain habitat (Baseline and HRL) generated using the LTO_12a flow run.

Other HRL commitments

We modeled additional commitments that were listed in the Memorandum of Understanding, Appendix 2:

Area	Total acres
Sutter Bypass, Butte Sink, and Colusa Basin	20,000 (floodplain)
Sutter Bypass, Butte Sink, and Colusa Basin	20,000 (fish food production)

Sacramento Floodplain improvements (Sutter, Colusa, Butte Sink)

• 20,000 acres were added to the Sutter Bypass watershed after the existing flow-to-area relationship was modeled using HRL flows.

• From December 1st to March 15th, Sutter Bypass will be assumed to have 20,000 acres of suitable habitat in each year.

20,000 acres fish food production

• To model the effects of 20,000 acres of fish food production, we calculated the available acreage for dry side floodplain for Sutter and Colusa basins using these data
• We then calculated the proportion of the committed 20,000 acres those acreages provide, and use that proportion to scale instream habitat for those watersheds.

• This will occur in every year from Jan 1st to Feb 28th

Watershed	Dry	Wet	Proportion
Colusa Basin	576,753	163	0.035
Sutter Basin	263,652	23,321	0.076