FLOOD10356

• County: Delta
• Title: North Fork Volunteer Water Quality Monitoring Project - April 2001-April 2002 Data Report
• Date: 9/30/2002
• Prepared For: North Fork River Improvement Association
• Prepared By: CSU Cooperative Extension and North Fork River Improvement Association
• Floodplain - Doc Type: Floodplain Report/Masterplan

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businesses, and private residences In the area utilize independent sewage disposal
systems (ISDS).

Current land uses in the study area are predominantly agricultural. Of the more than
1,000 parcels adjoining the river, 35 percent are classified as agricultural, consisting of
cattle and sheep ranches, crop production, and fruit orchards. Extractive industries
include underground coal mining, gravel mining, and logging. Tourism and outdoor
recreation supplement the general economy. The majority of riverfront property is
privately owned and used for agriculture, recreation, and gravel mining.

River Flows

The U.S. Geological Survey (USGS) collects river flow data along the Gunnison River
and its tributaries. Table 1.1 summarizes the stream flow gauging stations utilized by the
North Fork Volunteer Water Quality Monitoring Project.

Table 1.1 USGS Gaging Stations Used in Water Quality Monitoring Project

Drainage Maximum
Station Gauge Area Period of Flow
Station No. Type Location (sq. mi.) Record (cfs)
North Fork Gunnison 09132500 Streamflow 2.3 miles east 526 Oct. 1933 to 9,220
River: Above of Somerset current year (May 24, 1984)
Somerset
North Fork Gunnison: 09134100 Streamflow 1.5 southwest 741 Apr. 1936 to 2,980
Below Paonia of Paonia Sept. 1947, (May 6, 2000)
Oct. 1985 to
current year
North Fork Gunnison 09135950 Streamflow 0.7mi. 922 Mar. 1997 to 3,220
River Below Leroux downstream current year (May 24, 1999)
Creek from Leroux
Creek

Source: USGS, 2002.

A verag,e flows are highest during the spring snowmelt runoff months of May and April.
Major flooding may also occur during spring runoff months from rapid snowmelt that is
sometimes augmented by rain. Snowmelt flooding is characterized by moderate peak
flows, large volumes of runoff, and long flow duration. Flooding from rainfall is
characterized by high peak flows of moderate duration. Historical flood records date
back to 1917.

1.3 Historical Collection of Water Quality Data

Comprehensive monitoring of water quality in the North Fork watershed is conspicuously
lacking from the current body of water data for this region. The only on-going long-term
monthly monitoring site on the river is sampled by the Colorado Department of Public
Health and Environment (CDPHE) near the small town of Lazear. Other sampling efforts
by agencies such as the U.S. Geological Survey, the local mines, or the Colorado
Division of Wildlife (CDOW) have been of limited duration, or focused on only a
specific segment of the watershed. For example, in 1998, the USGS monitored for

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