WSP12263

• File Number: 8272.500
• Description: Colorado River Basin Salinity Control - Colo Dept of Public Health - WQCC and WQCD
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 10/1/1990
• Author: WQCD
• Title: Colorado Nonpoint Source Management Program - Prepared to Fulfill the Requirements of Section 319 of the Clean Water Act
• Water Supply Pro - Doc Type: Report/Study

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ChaDter IV.

Aariculture and Silviculture Nonooint Source Manaaement proaram

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Introduction

This agriculture/silviculture management program is prepared, by the
agriculture and silviculture subcommittee of the Colorado Nonpoint Source Task
Force, to fulfill the requirements of Section 319 of the Federal Clean Water
Act. The intent of the program is to identify means of controlling
agricultural/silviculture nonpoint source impacts identified in the Colorado
NonDoint Assessment Reoort. The management programs describe not only high
priority watersheds which require best management practices installation but
also statewide educational and research needs which will further advance the
knowledge of agricultural/silviculture nonpoint source impacts and control
practices in Colorado.

ImDacts of Aariculture and Silviculture NonDoint Sources

Agriculture/silviculture, for the purposes of this management program,
includes the cultivation of cropland, the raising of livestock; and the
harvesting of forest products. This broad definition of
agriculture/silviculture includes nonpoint source generating activities such
as irrigated and dryland farming, grazing activities, feedlots, tree
harvesting, and small road construction on public lands. The Colorado
NonDoint Assessment ReDort IJanuarv 1990\ delineates approximately 2,200 miles
of stream affected by these agricultural/silvicultural activities.
Additionally 16,000 surface acres of waterbodies are 'identified as impacted by
agriculture. Agriculture has been identified as impacting groundwater at
several locations within the state,

In Colorado the primary pollutants of concern from agriculture are sediment
and salinity (total dissolved solids). These pollutants occur naturally due
to the inherent erodibility of soils. Man's activities can greatly increase
the rate of erosion and lead to the siltation of stream beds, as well as lakes
and reservoirs. Siltation may lead to loss of aquatic habitat in both streams
and standing water bodies.

Nutrients such as phosphorus and nitrate which result from agricultural
activities also pose a threat to water quality. Application of fertilizers to
cropland may lead to increased nitrate levels in groundwater, and may
stimulate the growth of algae or nuisance weeds in lakes and reservoirs. High
levels of nitrate (in excess of 10 mg/l) in drinking water supplies pose a
threat to public health. Recreational activities in lakes and reservoirs may
be restricted by over enrichment of standing waters, which lead to
eutrophication.

NonDoint source Aaricultural and Silyicultural Manaaement Proaram priorities

The Colorado NonDoint Assessment ReDort indicates that agriculture nonpoint
impacts are felt throughout the state. This is particularly true of the
impacts of sediment and salinity. The impacts of nutrients, due to
agricultural activities, in standing waterbodies appear to be most severe in
the Platte River Basin. Groundwater impacts from agricultural practices are
largely unknown. The lack of a well coordinated database is a major roadblock
to understanding groundwater problems in Colorado.

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