General water chemistry and quality in newly-created subtropical wetland lake

Abstract

Sixty km2 of the southern Hula Valley (northern Israel) peat lands were flooded in 1994 as part of the Hula Valley Restoration Project. The small, shallow lake (110 ha, mean depth < 1 m) and network of ca. 90 km of canals created were designed to ameliorate problems (e.g., underground fires, soil subsidence, increased nutrient loading downstream to Lake Kinneret) resulting from drying the Lake Hula wetlands in the 1950s. This new wetland area now serves as the focus for developing eco-tourism in northern Israel. The initial development of this new ecosystem has been followed closely by a multi-disciplinary team of researchers, with an emphasis on water quality in the new lake and the potential impact of the project on Lake Kinneret. Here we report an overview of developments in general water chemistry of Lake Agmon during its first three years (1994–1996). Water quality in Agmon was within general expectations for a shallow lake situated on peat. The first year of Agmon was characterized by the heavy influence of stream and drainage inflows with high pH, alkalinity, turbidity and electrical conductivity and high concentrations of sulfate and total dissolved solids. By the third year, however, many “in lake” processes (e.g., nutrient cycling and algal and macrophytic production) were well-developed and thus strongly affected lake water quality. Excessive phosphorus and nitrogen concentrations in the lake have led to hypertrophy, characterized by low dissolved oxygen concentrations and prolific blooms of nuisance algae. The management of this new ecosystem in the near future will require persistent, and innovative measures.