Effects of Climate Conditions on TP Outsourcing in Lake Kinneret (Israel)

Since the mid-1980s, significant changes in climate conditions have occurred, and trends of dryness in the Kinneret drainage basin have been documented, including a temperature increase and precipitation decline. The precipitation decline, and consequently the reduction in river discharge, resulted in a decrease in TP (total phosphorus) flux into Lake Kinneret. After the drainage of the Hula natural wetlands and old Lake Hula during the 1950s, the ecological characteristics of the Hula Valley were modified. Nutrient fluxes downstream into Lake Kinneret were therefore predicted. The impacts of climate conditions (precipitation and discharge) on TP (total phosphorus) outsourcing through erosive action are significant: higher and lower discharge enhances and reduces TP load, respectively. The total TP flushing range from the Hula Valley peat soil through the subterranean medium and where TP is directed are not precisely known but are probably outside Lake Kinneret. Most runoff water and mediated TP originates from bedrock through erosive action. Long-term records of TP concentrations in headwaters and potential resources in the Hula Valley confirmed the significant influence of climate conditions on the outsourcing of TP capacity. The impacts of agricultural development, external fertilizer loads and migratory cranes in the winter are probably insignificant.

Absence of Surface Water Temperature Trends in Lake Kinneret despite Present Atmospheric Warming: Comparisons with Dead Sea Trends

This study was carried out using Moderate Resolution Imaging Spectroradiometer (MODIS) 1 km × 1 km resolution records on board Terra and Aqua satellites and in-situ measurements during the period (2003–2019). In spite of the presence of increasing atmospheric warming, in summer when evaporation is maximal, in fresh-water Lake Kinneret, satellite data revealed the absence of surface water temperature (SWT) trends. The absence of SWT trends in the presence of increasing atmospheric warming is an indication of the influence of increasing evaporation on SWT trends. The increasing water cooling, due to the above-mentioned increasing evaporation, compensated for increasing heating of surface water by regional atmospheric warming, resulting in the absence of SWT trends. In contrast to fresh-water Lake Kinneret, in the hypersaline Dead Sea, located ~100 km apart, MODIS records showed an increasing trend of 0.8 °C decade−1 in summer SWT during the same study period. The presence of increasing SWT trends in the presence of increasing atmospheric warming is an indication of the absence of steadily increasing evaporation in the Dead Sea. This is supported by a constant drop in Dead Sea water level at the rate of ~1 m/year from year to year during the last 25-year period (1995–2020). In summer, in contrast to satellite measurements, in-situ measurements of near-surface water temperature in Lake Kinneret showed an increasing trend of 0.7 °C decade−1.

Hydrology and Cranes (Grus grus) Attraction Partnership in the Management of the Hula Valley—Lake Kinneret Landscape

The Hula Valley in northern Israel was partly covered by swamps and a shallow lake. The entire valley was drained and converted for agricultural cultivation. Later, an additional soil reclamation operation was implemented, including eco-tourism. From the early 1990s, winter migratory cranes have attracted visitors, thus supporting the hydrological management of the entire valley that protects the downstream Lake Kinneret. It was documented that these birds have a minor impact on phosphorus pollution, but severely damaged agricultural crops are protected by mild deportation and daily, short, periodical corn seed feeding.