Climatic and hydrological aspects of the Hula restoration project

Drying the Hula marshes (northern Israel) in the 1950s caused changes in sub-surface hydrology that severely compromised agricultural sustainability of the Hula Valley peatlands. The complex dynamics between climatic and hydrological regimes produced widely fluctuating elevations in the water table, leading to deterioration of the peat soils through enhanced aerobic decomposition, wind erosion, and underground fires. The year-round intensive and diverse cropping systems used in 1960s were gradually replaced in the 1980s by extensive winter forage crops, leaving the peat uncropped and exposed to increased deterioration in the dry season. The Hula Restoration Project was initiated in 1993 to moderate some of these after-effects of the draining of the Hula marshes. The project includes a 90-km network of water-level regulating supply and drainage canals and a 100-ha lake and a barrier to underground water flow from the lake to cultivated areas. We followed changes in underground water levels for the five years before and the three years after re-flooding of the valley in May 1994. Prior to re- flooding, water tables in the area fluctuated 2–4 m annually, depending on location and microrelief and there was a strong north to south flow of water. After re-flooding the lake initially had a strong influence on water table elevation in the adjacent areas, which later stabilized. The underground barrier shifted the predominant water flow westward toward a north-south canal near the edge of the valley and then southward along the canal. The restoration project has been successful up to now, there are few underground fires since re-flooding, and all agricultural lands can be cultivated al year long.