Washington State Department of Ecology

Publication Summary

Title

Lower Skagit River Tributaries Riparian Vegetation Change Analysis Results

Month-Year Published

November 2007

Online Availability

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Short Description

Riparian vegetation was analyzed along six Lower Skagit River tributaries using GIS and orthoimagery. The tributaries were Carpenter, Fisher, Hansen, Lake, Nookachamps, and the East Fork Nookachamps Creeks.

The 2004 Lower Skagit River Tributaries Temperature Total Daily Maximum Load (TMDL) study determined that these tributaries have temperature impairments. The TMDL study also made recommendations for increasing shade-producing vegetation along the creeks.

This report summarizes the changes in vegetation as a result of voluntary shade enhancement efforts for the six creeks between the years 1990/1998 and 2006.

Report revised in April 2008: The boundary delineations of Carpenter, Fisher, and East Fork Nookachamps Creeks were revised to be consistent with uppermost Department of Ecology stream temperature sensors.

(Also see abstract below)

Publication Number

07-03-050

Author(s)

Meredith, C.

Print Availability

Request from the program.

Number of pages

Keywords

creek, lake, riparian, river, Skagit , temperature

Subject Waterbodies

Carpenter Creek,
Fisher Creek,
Hansen Creek,
Nookachamps Creek,
Nookachamps Creek,
E.F.

Related Publications

Title

Relationship

Lower Skagit River Tributaries Temperature Total Maximum Daily Load Study

similar topic

Abstract

Long Description

This purpose of this study was to measure changes in riparian vegetation along six Lower Skagit River tributaries: Carpenter, Fisher, Hansen, Lake, Nookachamps, and East Fork Nookachamps Creeks. These creeks have temperature impairments, as determined in the Lower Skagit River Tributaries Temperature Total Daily Maximum Load Study (Zalewsky and Bilhimer, 2004).

The Washington State Department of Ecology analyzed riparian vegetation changes within 50-foot and 150-foot buffer zones along all six tributaries. Orthoimagery and Geographic Information System (GIS) devices were used to delineate and compare vegetation and land types between the years 1990 (or 1998 depending on available data) and 2006.

Overall, the changes in riparian vegetation were not substantial:

Shade-producing vegetation increased slightly along Hansen and Nookachamps Creeks.

Shade-producing vegetation declined slightly along Carpenter and Lake Creeks.

There was little change in shade-producing vegetation along East Fork Nookachamps Creek, although some increases in dense shrubs and medium trees occurred in the 150-foot riparian zone.

Two categories of shade-producing vegetation increased along Fisher Creek, while dense, medium trees decreased.

There was a general increase in barren and non-vegetated lands along the six tributaries. This increase in barren areas may be related to the trend of decreasing grass/pasture lands. When all six tributaries were combined, tall, dense trees increased in area, and medium, dense trees decreased in area.

This page last updated October 8, 2008