My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
7922
CWCB
>
UCREFRP
>
Public
>
7922
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
7/14/2009 5:02:31 PM
Creation date
6/1/2009 11:33:08 AM
Metadata
Fields
Template:
UCREFRP
UCREFRP Catalog Number
7922
Author
Bovee, K. D.
Title
A Guide To Stream Habitat Analysis Using The Instream Flow Incremental Methodology, Instream Flow Information Paper No. 12.
USFW Year
1982.
USFW - Doc Type
\
Copyright Material
NO
Jump to thumbnail
< previous set
next set >
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
273
PDF
Print
Pages to print
Enter page numbers and/or page ranges separated by commas. For example, 1,3,5-12.
After downloading, print the document using a PDF reader (e.g. Adobe Reader).
Show annotations
View images
View plain text
the project and by imposing project operations on the historical flows to <br />develop a new flow time series. One way to define the impact of the project <br />is to integrate the areas beneath the habitat time series with and without the <br />project and find the difference. A habitat duration curve summarizes the <br />habitat time series in terms of the percent of time a certain amount of habitat <br />is equalled or exceeded, with and without the project. Biologically signifi- <br />cant impacts can be defined by the area under the habitat duration curve, <br />between the 50% and 90% probabilities of exceedance. The habitat duration <br />curve can also be used to express an impact in terms of frequency rather than <br />amount. <br />The effective habitat time series uses estimates of the relative spatial <br />requirements between life stages or trophic levels (called habitat ratios) to <br />compute the habitat requirements for each life stage at a particular time. A <br />life table is compiled, comparing the required habitat for any time step in <br />the time series with the amount available. If the amount available exceeds <br />the amount required, then the required amount is carried forward to compute <br />the habitat required for the next life stage during the next time step. The <br />available amount of habitat is carried forward when it is less than the <br />required amount. The effective habitat time series estimates the amount of <br />adult habitat that can be utilized over time and incorporates lags in habitat <br />utilization resulting from extreme events or water supply patterns that affect <br />several life stages at once. A version of the effective habitat time series, <br />based on a steady state population and probabilistic hydrology, can be used to <br />construct an instream flow regime that ties the flow requirement for any month <br />with those for all other months. <br />Habitat ratios are extremely useful in the interpretation of habitat- <br />related data and can be derived by professional judgement, historical evidence, <br />comparisons among streams, and by mathematical derivation. Habitat ratios <br />among life stages are functions of the age-biomass distribution of the popula- <br />tion, and the densities and survival rates of each life stage. Generally, <br />subadult life stages require relatively less space than the adult phase. <br />Habitat ratios among trophic levels are affected by the relative production <br />rates at each level, the energy transfer efficiency between levels, the <br />cropping efficiency, and the relative proportion of a food item in the diet. <br />Because of the difficulty in determining each of these factors, the best <br />estimate of trophic level habitat ratios may be derived by establishing a <br />relationship between the habitat ratios for several streams and the condition <br />factor for the fish in each stream. A method of estimating total community <br />food requirements and supply is proposed in Appendix B. <br />In a typical application of the IFIM, the investigator must compute or <br />obtain an estimate of the water supply on which the instream flow recommenda- <br />tion or mitigation plan is based. Chapter 6 outlines several techniques for <br />synthesizing hydrographs in gaged and ungaged streams, and discusses considera- <br />tions of reservoir operations. The concept of water budgets or water balances <br />is also introduced. The water budget plays three important roles in the IFIM. <br />First, because the instream flow recommendation is based on the computed <br />available water supply, the water budget helps establish credibility with <br />water managers. Second, the instream flow recommendations for several streams <br />can be integrated into a cohesive, internally consistent network. Third, the <br />viii
The URL can be used to link to this page
Your browser does not support the video tag.