Home Miracle at Work Healthy Forests Cool Stuff for Teachers Cool Stuff for Kids Search/Directory  









Stream Protection Zone (SPZ)

SPZ Boundaries

  • Designate streamside protection zones to provide stream shading, soil stabilization, sediment and water filtering effects, and wildlife habitat.
  • "Stream" means a natural watercourse of perceptible extent with definite beds or banks that confine and conduct continuously or intermittently flowing water.
  • Definite beds are defined as having a sandy or rocky bottom that results from the scouring action of water flow.
  • The SPZ encompasses a strip at least 75 feet wide on each side of a Class I stream, measured from the ordinary (yearly average) high-water mark or definable bank. The SPZ on a Class II stream is 30 feet or more away from the ordinary high water marks. An exception is on Class II streams that do not drain into Class I streams; then the SPZ is five feet.
  • The width of the SPZ can extend beyond the 75-foot minimum to include wetlands along the stream bottom and to provide additional protection in areas of steep slopes or erosive soils.
  • Consult with forestry professionals, soil and water conservation specialists, or biologists if assistance is needed in setting appropriate SPZ boundaries.

What is a stream?

A stream can be identified in one of two ways. A stream must have a sandy or gravel bottom, the result of flowing water. Or a stream must have definite banks that restrict water.
When no definite bank is apparent, watch for where sand or gravel stops and soil begins at the edge of a stream.

Is this a stream?

No (picture right). There is no rocky bottom or identifiable banks. But this is an ephemeral area, part of the watershed collection system that may carry water during high flows. Disturbed soils in these areas can create sediment (see Watersheds). Care should be taken when logging.

Setting SPZ Boundaries

To be sure equipment operators have no question about the SPZ boundary it should be clearly marked. Plastic flagging, paint, or signs should be used at frequent intervals. The purpose of marking an SPZ is to be sure everyone working around a stream, lake, or other body of water knows the extent of the protected area.

These areas require an SPZ of no less than 75 feet. It is measured from the ordinarily high-water mark or definable bank. Watered streams are easy to identify, intermittent streams can be more difficult to identify during dry periods. Whether wet or dry, perennial or intermittent, during droughty or rainy years, streams must.

One reason for a wider SPZ is be protected with an SPZ. When a wetland lies adjacent to a stream, individuals must be aware of wetlands by watching for water-loving plants. In these cases, the SPZ must loop out to include any wetland and provide protection. Proper SPZ location requires practice and personal judgment.

What is a wetland?

Wetlands include seeps, springs, wallows, marshes, and bogs. They collect and hold water.


More SPZ Information:   < < Last  |  Next > >




BACK TO BMP INDEX   TOP OF PAGE
Idaho Forest Products Commission
©2005 All rights reserved.