GROUNDWATER DISCHARGE AND ITS IMPACT ON SURFACE WATER QUALITY IN A CHESAPEAKE BAY INLET1

ABSTRACT: Surface water, groundwater, and groundwater discharge quality surveys were conducted in Cherrystone Inlet, on Virginia's Eastern Shore. Shallow groundwater below agricultural fields had nitrate concentrations significantly higher than inlet surface waters and shallow groundwater underlying forested land. This elevated nitrate groundwater discharged to adjacent surface waters. Nearshore discharge rates of water across the sediment-water interface ranged from 0.02 to 3.69 liters·m^?2·hr^?1 during the surveys. The discharge was greatest nearshore at low tide periods, and decreased markedly with increasing distance offshore. Vertical hydraulic heads, E_h, and inorganic nitrogen flux in the sediments followed similar patterns. Nitrate was the predominant nitrogen species discharged nearshore adjacent to agricultural land use, changing to ammonium farther offshore. Sediment nitrogen fluxes were sufficient to cause observable impacts on surface water quality; nitrate concentrations were up to 20 times greater in areas of groundwater discharge than in the main stem inlet water. Based on DIN:DIP ratios, nitrogen contributions from direct groundwater discharge and tidal creek inputs appear to be of significant ecological importance. This groundwater discharge links land use activity and the quality of surface water, and therefore must be considered in selection of best management practices and water quality management strategies.     

Nestmate discrimination in social wasps (Polistes metricus,Hymenoptera: Vespidae)

Summary Laboratory-overwintered paper wasp (Polistes metricus) females preferentially associate on new nests with former nestmates (presumably their sisters) rather than with non-nestmates in the absence of cues associated with their natal nests or nest sites. Females isolated from conspecifics and nests for 74–99 days retain the ability to discriminate nestmates from nonnestmates.     

WATER AS A COMMODITY IN INTERNATIONAL TRADE1

International trade in water has been pioneered by coastal or island city-states, by areas subject to boundary revision after a water supply system had been established, by informal accommodations among good neighbors, and by co-riparians agreeing to negotiate on compensation as an element in water allocation. Specific examples are described. Formulations of criteria for an equitable agreement for possible transfers of Canadian water to the United States have been published by Laycock and by Kuiper. Many other Canadians have expressed serious concern over the long-range implications of water export and have frequently proposed restrictions which they believe that Canada should insist upon in any negotiations. Explicitly or implicitly in nearly all Canadian discussion of water export is the conviction that international transfer, should it be permitted at all, should occur at some mutually satisfactory point or points on the border with all questions or sources and routes within Canada being left to the agencies within Canada selected by the Canadians for the task.