Forest Management 101

• Assistance / Programs
• BMPs
• Easements
• Forest Health
• Fragmentation
• Native Plants
• Non Timber Products
• Recreation
• Water Quality
• Wildlife

View Select Publications Related to Water Quality

Water Quality

This general introduction to the complex issue of water quality is intended to stimulate interest by private forest landowners. The subject of water quality is extensive and covers many different fields; this page presents a broad view of some of the key issues and implications of water quality to help visitors locate information in the ConserveOnline library.

Introduction

Management Strategies

Links

Introduction

Aquatic resources are among our most valuable assets. Although 70 percent of the Earth's surface is covered with water, the amount of fresh water available on land surfaces is a tiny fraction of the total;

• 97.5 percent of the water on the planet is in the oceans - too salty to drink or to grow crops.
• Of the remaining 2.5 percent, the majority is locked up in the vast icecaps of Greenland and Antarctica.
• Less than 1 percent of the water on the planet is fresh water that is accessible to plants and animals, in groundwater, on the land surface in rivers and lakes, and in the atmosphere (see figure 1 below).

Figure 1.

This image provided by USDA FS, Publication FS 660,Water & The Forest Service

Water is continuously cycled between the Earth's surface and atmosphere through evaporation and precipitation. The fresh water that falls on land as rain or snow, or that has been accumulated and stored over thousands of years as groundwater, is what people use to meet most of their needs. That supply, although replenished daily, is vulnerable to human actions and abuse. Over appropriated rivers and excessive groundwater pumping are serious problems. Many of America's important food-producing regions are sustained by the hydrologic equivalent of deficit financing- using water that is not being replaced.

While all types of waters are renewable, the rates of renewal differ sharply. Water in rivers is completely renewed every 16 days on average, and water in the atmosphere is renewed every 8 days, but the renewal periods of glaciers, groundwater, ocean water, and the largest lakes run to hundreds or thousands of years. These are, essentially, nonrenewable resources. When people use or degrade these water supplies, useable water resources are lost and natural water cycles may be disrupted. About 80 percent of the scarce freshwater resources in the United States originate in forests, which cover only about one-third of the country's land area. Healthy and well-managed forests are thus vital to the supply of water.

Management Strategies

Forested watersheds have a well-deserved reputation for producing clean water. The forested land absorbs rain, refills underground aquifers, removes impurities, slows storm runoff, reduces flooding, sustains watershed stability and resilience, and provides critical habitat for fish and wildlife. The quality of water in undisturbed forests and grasslands is usually good, but research suggests that the water quality of managed ecosystems depend on the particular land-use practices being implemented. Some land-use practices can protect or restore water quality, but others may degrade or pose risks to clean water. Activities associated with forest harvesting and silvicultural practices can impair water quality, unless best management practices (BMPs) are implemented. The United States Forest Service has formulated standards for timber management activities designed to protect water quality in these areas, which they refer to as Streamside Management Zones (SMZs).

The SMZ is divided into two adjacent zones: primary and secondary. The primary SMZ is the vegetation that directly surrounds a body of water, and consequently provides water quality protection by maintaining shade and bank stability, and by filtering water moving into the water. Thus, only non-intensive forest management activities should be practiced in the primary SMZ. Primary SMZ boundaries should be determined before operations begin, when streams are running within their channels. The Forest Service uses the following guidelines, which are used based on slope of land and width of the streams:

For slopes less than 20 percent, the Primary SMZ width should be at least:

• 35 feet on each side of a stream that is less than 20 feet wide
• 50 feet on each side of a stream that is 20 to 50 feet wide, or
• width of stream up to 100 feet maximum for a stream wider than 50 feet.

For slopes 20 percent or greater, the Primary SMZ should be at least:

• to the top of the slope or 150 feet, which ever is less, on each side of the stream, regardless of the width of the stream.

The secondary SMZ is a transition zone between the primary SMZ and the rest of the forest. It reduces the amount of sediment and debris moved into the primary SMZ. The need for a secondary SMZ is based on slope. The average slope for the 50 feet adjacent to the primary SMZ will determine the width of the secondary SMZ.

The secondary SMZ should be at least:

• 50 feet for slopes greater than 7 percent but less than 20 percent.
• 75 feet for slopes greater than or equal to 20 percent.

The rational use and protection of water resources are among today's most acute and complex scientific, technical, and political issues. Traditionally, water has been valued as an engine of development and as the source of commodity and utilitarian values to society. It has sustained agricultural production, grown forests, and powered cities and industries. Water is the basis for many of the recreational and amenity values people seek. Increasingly, science shows, and managers recognize, the key role of water flow regimes in ecosystem function and processes. Adequate flow and water quality are essential to maintaining key fish species and fisheries, which in turn, are sources of many economic, cultural, and spiritual values. Across the country, resource managers, scientists, and citizens face both significant technical challenges as well as emerging conflicts over how to provide high quality, abundant flows of water to sustain a burgeoning population, an agricultural industry, historic salmon runs, and populations of other threatened aquatic species.

Links

All links take you out of the ConserveOnline Library for Private Forest Landowners

United States Environmental Protection Agency (EPA)

Office of Water: Forestry
This site provides links to EPA documents on forest management and water quality, laws and policies, educational information and links to other useful sites on water quality as it relates to forest management.

Surf Your Watershed

This U.S. EPA site allows you to locate the watershed you live in and view important facts regarding its health. There site also offers extensive links arranged by state, full text search, information type (i.e. data, maps, services, or text), and keywords.

USDA Natural Resources Conservation Service (NRCS), Buffer Strips: Common Sense Conservation

This is the site for the NRCS National Conservation Buffer Initiative, which seeks to enhance 2,000,000 miles of conservation buffers along rivers and streams in the United States. Read about the work of buffers, the Initiative and it's partners, and, of course, cool links about buffers.

USGS

A Primer on Water Quality
Read the USGS primer on water quality, particularly how the issues affect human health.

Other Resources

American Water Resources Association

This site posts information on conferences and publications related to water-related issues.

American Rivers

This site offers links to documents, conservation tools, current events in water-related issues, contact information for river and water conservation organizations.