17 



High nutrient levels have created eutrophic conditions in 

 all the small ponds and reservoirs on the Highwood Bench. Almost 

 all the wells, springs, and reservoirs on the bench, which were once 

 fresh, are now highly saline. And many of the reservoirs that once 

 produced trout no longer support a sport fishery. The EPA National 

 Field Investigations Center, Cincinnati, at the request of the Governor's 

 Saline Seep Committee and the EQC, will conduct a limnological 

 reconnaissance of these reservoirs to determine the exact cause or 

 causes of fish disappearances. 



The demise of Highwood Bench reservoirs has been linked to 

 the acceleration of saline seeps. Three characteristics of saline seep 

 waters- -TDS, heavy metals, and nutrients- -alone or in combination, 

 are the suspected causative agents for fish mortalities in these waters. 



Levels of heavy metals in at least one reservoir on the 

 Highwood Bench (Table 1) exceeded recommended water quality standards 

 for fish and aquatic life (20). TDS were also above recommended levels 

 for freshwater life, and nitrate was extremely high in the one reservoir 

 sampled. As noted in Table 1 nitrate is one of the major components 

 of the salt deposited by seeps on the bench and may be partly responsible 

 for eutrophication of area reservoirs. Although increased aquatic plant 

 growth may have depleted oxygen levels and thereby be the single cause 



