In the Tulare Basin of California some farm operators have constructed large basins to evaporate drainwater high in salts. These basins have provided highly productive feeding and nesting habitat for shorebirds in this wetland-sparse region, but the water also contains toxic amounts of selenium and boron, which cause severe embryonic deformities and reproductive failure in this population of birds. 

In 1996, the Service and others won a petition to the State Water Resources Control Board (State Board) resulting in the preparation of new Waste Discharge Requirements by the Central Valley Regional Board (Regional Board) for operators who had not earlier settled with the Service. In addition, those operators were directed to rectify their previously inadequate Environmental Impact Reports (EIRs). 

The pond owners which have settled with the petitioners are using Service developed protocols to determine the acreage of mitigation needed for each evaporation pond system.  The protocols use selenium concentration in shorebird eggs, evaporation pond size and attractiveness, and other parameters to determine the appropriate wetland acres needed. The results of nearly 10 years of research by the Service and others were used to develop the protocols. It provides incentives to pond owners to make their ponds less attractive to shorebirds thus reducing the risk of exposure and then providing for alternative habitat to draw birds away from the ponds. Compensation habitat is then determined to address any remaining unavoidable impacts.  Depending on the variables used in the protocols as many as 2,000 acres of alternative habitat and 900 acres of compensation habitat may be created in the Tulare Basin. 

The current status is that 23 percent of 1993 evaporation pond acreage is mitigated via Service protocols, 5 percent are closed or closing,  another 5 percent are following the protocols but must do their EIRs again, and 68 percent are not adequately mitigated and must receive a new waste discharge requirement (after completion of the EIR process). The Service is reviewing Monitoring Assessment Reports and providing input on waste discharge requirements to the Regional Board. We also continue to monitor shorebird egg selenium levels in the Tulare Basin to evaluate the effectiveness of the newly constructed wetland habitats.

Service biologist "floating" a shorebird egg to determine its stage of development. East edge of Tulare Lake Basin.