Application of the Montana Nonpoint Source Stream Reach Assessment 



Figure E-2: Nonpoint Source Stream Reach Assessment Overview 



INTRODUCTION : NONPOINT SOURCE (NPS) POLLUTION IS HIGHLY DIFFUSE IN NATURE, UNLIKE POINT SOURCE POLLUTION UHICH CAN 

 BE ATTRIBUTED TO A SINGLE POINT. NPS POLLUTION DISCHARGES OCCUR OVER DISPERSED PATHWAYS AND ARE GENERALLY 

 ASSOCIATED WITH PRECIPITATION AND RUNOFF. NPS POLLUTION IS RELATED TO NUHAN LAND USES UHICH ARE CONTROLLABLE. 

 BEST MANAGEMENT PRACTICES (BNP'S) ARE METHODS INCORPORATED WITH LAND USES THAT AVOID OR MINIMIZE IMPACTS TO WATER 

 RESOURCES CAUSED BY J<PS POLLUTION. 



PURPOSE : THIS ASSESSMENT PROCEDURE IS DESIGNED FOR STATEWIDE USE TO PROVIDE AN INITIAL, STANDARDIZED METHOD TO 

 IDENTIFY NONPOINT SOURCES, APPRAISE BMP APPLICATION AND EFFECTIVENESS AND ASSESS STREAM IMPAIRMENTS THAT HAVE 

 RESULTED FROM NONPOINT SOURCE (NPS) POLLUTION. HYDROLOGIC FACTORS THAT CONTRIBUTE TO IMPAIRMENT OF THE STREAM WILL 

 ALSO BE ASSESSED. THE WATER QUALITY BUREAU (WQB) WILL ASSIGN NUMERICAL RATINGS TO EACH ASSESSMENT PARAMETER WHICH 

 WILL CATEGORIZE STREAMS RELATIVE TO DEGREE OF IMPAIRMENT. STREAMS CATEGORIZED AS SEVERELY IMPAIRED WILL RECEIVE 

 EMPHASIS FOR FUTURE NPS POLLUTION MANAGEMENT. INFORMATION FROM THE ASSESSMENTS AND THE SUBSEQUENT RATINGS WILL 

 PROVIDE A UNIFORM DATA BASE FOR EACH STREAM AND STREAM REACH. THIS DATA BASE WILL BE STORED IN THE MONTANA REACH 

 TRACKING SYSTEM DEVELOPED BY THE WQB. INFORMATION IN THE REACH TRACKING SYSTEM WILL BE AVAILABLE TO INTERESTED 

 INDIVIDUALS. 



INSTRUCTIONS : THE ASSESSMENT PROCEDURE WILL BE LIMITED TO SECOND, THIRD AND FOURTH ORDER STREAMS^. THE DISTANCE OF 

 EACH STREAM REACH ACTUALLY OBSERVED IS DEPENDENT ON FACTORS SUCH AS TIME OR ACCESSIBILITY. OBVIOUSLY THE BEST 

 ASSESSMENT WOULD INVOLVE WALKING THE ENTIRE STREAM. REALISTICALLY THIS WILL NOT BE POSSIBLE IN MOST SITUATIONS AND 

 IS NOT NECESSARY. AS A GENERAL GUIDE THE SURVEYOR SHOULD CHOOSE THE MOST ACCESSIBLE OBSERVATION POINTS THAT ALLOW 

 ADEQUATE IDENTIFICATION OF IMPAIRMENTS THAT MAY BE OCCURRING IN A REACH. EXAMPLES WOULD BE AT THE STREAM MOUTH. 

 ABOVE AND BELOW HUMAN ACTIVITIES AND BELOW TRIBUTARIES. THE SURVEYOR SHOULD WALK AT LEAST 100' OF THE STREAM AT 

 EACH OBSERVATION POINT OR ENOUGH DISTANCE TO GET A REPRESENTATIVE PICTURE OF THE SITUATION AT THAT POINT. IF 

 POSSIBLE, TRY TO INCORPORATE A RIFFLE. RUN AND POOL AT EACH OBSERVATION POINT. 



EACH STREAM WILL CONSIST OF ONE OR MORE REACHES. ONi ASSESSMENT FORM WILL BE COMPLETED FOR EACH REACH. STREAM 

 REACHES WILL BE DETERMINED BY THE SURVEYOR. EACH REACH SHOULD EXHIBTT FATRI Y HOMOGENOUS CONDITIONS. AS A GENERAL 

 RULE REACH BREAKS OCCUR WHERE OBVIOUS CHANGES IN STREAM CONDITION ARE DETECTED. THE SURVEYOR SHOULD BE AWARE OF 

 CHANGES SUCH AS LAND PRACTICES, FLOW, GRADIENT, VEGETATION, VALLEY TOPOGRAPHY AND SUBSTRATE. 



CONSIDER THE ENTIRE REACH WHEN RATING PARANETERS. AVOID CONCENTRATING ON SPECIFIC FEATURES UNLESS THEY ARE A MAJOR 

 PROBLEM. PLEASE RATE Ay. PARAMETERS ON THE FORM AND CHOOSE THE DESCRIPTION THAT IS MOST APPLICABLE. DO NOT LEAVE 

 ANY RATING PARAMETERS BLANK. IN CASES WHERE RATING FACTORS DO NOT APPLY RECORD AS N/A; OR IF A PARAMETER RATING IS 

 UNKNOWN RECORD AS SUCH. 



TOPOGRAPHIC HAPS AT A MINIMUM AND AERIAL PHOTOS (IF POSSIBLE) SHOULD BE CONSULTED PRIOR TO THE ASSESSMENT TO PICK 

 OUT PROMINENT FEATURES IN THE WATERSHED AND TO SELECT OBSERVATION POINTS. MAPS WITH IDENTIFICATION OF OBSERVATION 

 POINTS, REACH BREAKS, AND ANY IMPORTANT FEATURES SHOULD BE TURNED IN WITH ASSESSMENT FORMS. 



ANY OUTSTANDING FEATURES OBSERVED I.E. GROSS SEDIMENT SOURCES, FISH BARRIERS, POINT SOURCE DISCHARGES, ETC. SHOULD 

 BE PHOTOGRAPHED (IF POSSIBLE) AND LABELED ON THE MAP TO BE TURNED IN WITH THE ASSESSMENT FORM. 



EQUIPMENT : AT MINIMUM YOU WILL NEED FIELD FORMS AND MAPS TO DO ASSESSMENTS. IT IS SUGGESTED THAT THE SURVEYOR 

 INCLUDE A THERMOMETER IF IRRIGATION RETURNS ARE EXPECTED TO BE ENCOUNTERED, AND A CAMERA TO PHOTOGRAPH ANY NOTABLE 

 FEATURES ALONG THE STREAM. 



FOR DEFINITION OF STREAM ORDER SEE PAGE 1 OF ASSESSMENT FORM UNDER GENERAL INFORMATION. 



f^8e74 Flathead Basin Cooperative Program Final Report 



