Walnut Creek IA 05-NSH-1449

mouth (S8 T69N R41W Fremont Co.) to confluence with unnamed tributary at the S30/31 line in T73N R38W Montgomery Co.

This is a Legacy Assessment. Prior to 2004, assessments were developed under a methodology that pre-dated the Integrated Report guidelines.

Assessment Cycle

2002

Result Period

1998 - 2000

Designations

Assessment Methodology

2002 Methodology Document

Assessment Type

Evaluated

Integrated Report

Category 0

Legacy ADBCode

IA 05-NSH-0100_1

Overall Use Support

Partial

Aquatic Life Use Support

Partial

Fish Consumption

Not assessed

Documentation

Assessment Comments

Assessment is based on results of 1996 Biocriteria sampling: Fish IBI= 23(poor), 20(poor); BM-IBI= 53(fair), 45(fair).

Basis for Assessment

SUMMARY: The Class B(WW) aquatic life uses remain assessed as "partially supported." The assessment category, however, is changed from "monitored" to "evaluated." Fish consumption uses remain "not assessed." EXPLANATION: Continue to use the assessment developed for the 1998 report (see above) that was based on results of the 1996 IDNR biocriteria assessment. However, because these data are now considered too old (greater than five years) to accurately characterize current water quality conditions, the assessment category is changed from "monitored" (indicating an assessment with relatively high confidence) to "evaluated" (indicating an assessment with relatively low confidence). Fish consumption uses remain "not assessed" due to the lack of fish contaminant monitoring in this stream segment.

Monitoring and Methods

Assessment Key Dates

10/14/1996	Biological Monitoring

Methods

330	Fish surveys
380	Quan. measurements of instream parms-- channel morphology-- floodplain-- 1-2 seasons-- by prof
220	Non-fixed station physical/chemical monitoring (conventional pollutant only)
315	Regional reference site approach
320	Benthic macroinvertebrate surveys

Monitoring Levels

Biological	4
Habitat	4
Physical Chemistry	1
Toxic	0
Pathogen Indicators	0
Other Health Indicators	0
Other Aquatic Life Indicators	0
# of Bio Sites	2
BioIntegrity	Fair

Causes and Sources of Impairment

Causes	Use Support	Cause Magnitude	Sources	Source Magnitude
Other habitat alterations	Overall Use Support	High	Agriculture Bank or Shoreline Modification/Destabilization Channelization Crop-related Sources Grazing related Sources Habitat Modification (other than Hydromodification) Hydromodification Pasture grazing - Riparian	High High High Moderate High High High High
Other habitat alterations	Aquatic Life Support	High	Agriculture Bank or Shoreline Modification/Destabilization Channelization Crop-related Sources Grazing related Sources Habitat Modification (other than Hydromodification) Hydromodification Pasture grazing - Riparian	High High High Moderate High High High High
Siltation	Overall Use Support	Not Impairing	Agriculture Bank or Shoreline Modification/Destabilization Channelization Crop-related Sources Grazing related Sources Pasture grazing - Riparian	High High High Moderate High High
Siltation	Aquatic Life Support	Not Impairing	Agriculture Bank or Shoreline Modification/Destabilization Channelization Crop-related Sources Grazing related Sources Pasture grazing - Riparian	High High High Moderate High High