Management Guidelines for Riparian Forests 



tuted to place soils in one of the three classes. 



The practical guidelines for delineating 

 Streamside Management 2^nes are based on 

 current knowledge. As additional knowledge is 

 gained from current studies and experience, 

 SMZ criteria and BMPs should both be modi- 

 fied to provide a proper balance between pro- 

 tection of water quality and efficientiy meeting 

 objectives of the landowners. 



A 25-foot minimum SMZ was originally 

 recommended by the Environmental Quality 

 Council ' s Best Management Practices commit- 

 tee. The Montana Riparian Association Man- 

 agement Guidelines Working Group discussed 

 the minimum at their final meeting in March, 

 1 99 1 . After weighing the minor advantages and 

 disadvantages of 25 feet vs. 50 feet, they agreed 

 to recommend a 50 foot minimum as a reason- 

 able compromise in the context of current BMPs 

 within the Streamside Management Zone. 



Results - Soil Erodibility Matrix 

 Risk Assessment 



The results of a group expert opinion con- 

 sensus process (Delphi approach) to develop 

 the soil/slope risk assessment matrix are sum- 

 marized as Chapter One of Lull's Masters thesis 

 (Lull 1990). TTie round two matrix was also 

 used as an aid in conducting the 1 990 state- wide 

 BMP field audits (Schultz 1990). The Working 

 Group revised the matrix to obtain internal 

 consistency at their meeting on March 6, 1991. 

 This revised matrix is shown in Figure G-2. 



The Management Guidelines Working 

 Group considered several alternatives to the 

 parentmaterialclassesofClineandothers(1981) 

 for estimating soil erodibility. Fairly close agree- 

 ment was reached on soil texture in the round 

 two Delphi questionnaire. However, current 

 research by Ed Burroughs (USDA-Forest Serv- 

 ice-Intermountain Station, Moscow, ID) sug- 

 gests that the amount and shape of coarse fi-ag- 



ments may be equally important. Also, USDA- 

 Northem Region Hydrologists are currently 

 working on revised information on soil erodi- 

 bility for input into improved sediment models. 

 The Working Group decided (August 6, 1990) 

 to defer further work on soil erodibility and wait 

 for the results of the current efforts. When better 

 estimates of soil erodibility become available 

 they can be substituted to place soils in one of 

 our three classes. We think it is important to 

 keep the methods for estimating soil erodibility 

 consistent for risk assessment, streamside man- 

 agement zone formulas, and sediment models. 



Conclusions 



(1) Habitat type-specific management in- 

 formation has now been provided in a 

 1990 draft publication (Boggs and oth- 

 ers 1990). This information is far more 

 suitable than previous generalities and 

 better suited to aid field people in mak- 

 ing site-specific evaluations. 



(2) Criteria have now been developed and 

 evaluated for consistent field deline- 

 ation of Streamside Management Zones 

 to meet the intent of the Best Manage- 

 ment Practices. Additional suggestions 

 are provided for special situations where 

 the general formula should be adjusted 

 to provide additional protection. 



(3) A forest practices risk matrix in rela- 

 tion to slope and soil erodibility is now 

 available to evaluate relative risks. It 

 can be applied for watershed level risk 

 assessment of proposed alternative 

 practices and for several other applica- 

 tions and interpretations. Acknowledg- 

 ment of relative risk is the first step in 

 prescribing activities and possible miti- 

 gation. 



Flathead Basin Cooperative Program Final Report 



Page 101 



