Hydrologic response in the karstic and basaltic hydro-geological units of Lake Kinneret watershed
2020
Ben Yona, Matan | Rimmer, Alon | Shamir, Eylon | Litaor, Iggy
The hydrologic responses of two similar in size watersheds in the Lake Kinneret basin are examined: Karstic Hermon watershed and basaltic Meshushim watershed. The streamflow properties at these watersheds are different in their surface flow to baseflow ratio, runoff coefficients and response to extreme rainfall events. The HYdrological Model for Karst Environment (HYMKE) model, developed to simulate daily flow in karst formation, was modified to address the basaltic formation at the Meshushim watershed. Water fluxes simulations were used to compare the hydrologic processes between the watersheds. The twice-higher annual precipitation in the Hermon watershed, generates annual streamflow that is five times more than in the Meshushim. This amplification of the rainfall-streamflow ratio between the watersheds is because larger fraction of the rainfall is lost to evapotranspiration at the basaltic Meshushim watershed and larger portion of the rainfall percolates to the karstic aquifer through preferential flow and appear as baseflow at the Hermon watershed. During large rainfall events when soil water content is near saturation, lower rainfall amount over the Meshushim watershed generates larger peak flow than the Hermon watershed. In both watersheds, surface flow was generated only when the soil water content is at or near saturation conditions. The streamflow dependency on soil water content, suggests high sensitivity of streamflow generation to the intra-annual variability of precipitation. Understanding the hydrologic response of the different sources of Lake Kinneret improves the ability to forecast its inflow.
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