122 



AGRICULTURE 



Grazing Practices 



Range management has also damaged the fishery resource. Livestock are at 

 times still given free access to streams. They trample the bank, accelerating 

 erosion and reducing bank vegetation and instream cover. SCS has recognized 

 instream values and has begun to assist farmers to remedy these problems. 



Sedimentation 



Agricultural practices tend to increase stream siltation and sedimentation. 

 When streambank vegetation is cleared for grazing or row crops, there is an 

 increase in bank erosion. Cattle trampling streambanks causes sedimentation. 

 Run-off from tilled farmlands results in a higher silt load. 



Agricultural Pollution 



Agricultural pollution has long been recognized as a major detriment to water 

 quality and fish survival in the Chehalis Basin (Pickett 1992), and is the 

 object of extensive improvements statewide (Troy Colley, Grays Harbor 

 Conservation District, pers. cotnm. ) . Agricultural sources include farms, 

 feedlots, and tree plantations. Agricultural pollution falls into two major 

 categories: animal waste and toxic chemicals. 



Improper animal waste management, especially from dairy herds, allows plant 

 nutrients and pathogenic bacteria to enter surface waters (Diane Harvester, 

 WDOE, pers. cotnm.). Manure is at times improperly collected, stored, or 

 spread on fields, then rain washes bacteria and nutrients into the stream, 

 contributing to contamination and overnourishment (Pickett 1992). In 

 particular, there is a problem with low DO on the Black River and Gerrard 

 Creek (Diane Harvester, WDOE, pers. cotnm.). 



Pesticides and herbicides may enter streams when improperly applied or when 

 equipment is improperly cleaned. The degree of pollution cannot be easily 

 assessed because these chemicals tend to enter the stream from one particular 

 spill or other event, do their damage, then dilute or break down before they 

 can be identified or traced to their source. Lincoln and Independence Creeks 

 have had several fish kills in recent years, probably caused by improper 

 application of agricultural chemicals (Jay Hunter, WDW. , pers. comm. ) . 



Aqua culture 



There are four commercial fish farms located in the vicinity of Rochester to 

 take advantage of abundant groundwater. Aquaculture discharge poses a 

 potential risk to natural fish production from either chronic conditions, such 

 as from removal of fish wastes and algae during pond cleaning, or short-term 

 events, such as accidental spills of toxic chemicals used to sterilize ponds 



67 



