Hydrogeological characterization of an altered wetland

M. Iggy Litaor*, G. Eshel, R. Sade, A. Rimmer, M. Shenker

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Spatiotemporal changes in the hydrogeology of the Hula altered wetland may influence the water quality of Lake Kinneret, which provides up to 30% of the potable water for the state of Israel. The main objectives of this work were to study the groundwater-flow characteristics in this wetland and assess the potential impact on downstream water quality. We constructed variograms of hydraulic heads, computed decision-tree models of major ions, and determined the hydraulic conductivity (K) and δ2H/δ18O ratios, to ascertain the spatial and vertical distribution of hydrogeological parameters. We also performed large-scale field experiments (≥1 km2) to assess the connectivity between the waterways and the wetland's aquifer. The aquifer is fragmented by three parent materials: deep peat, shallow peat/marl complex and marl. The decision-tree-based model, the isotopic ratios and K determinations suggest that the deep peat subaquifer is composed of one homogeneous layer characterized by low K (0.001 m d-1). The two other subaquifers consist of three hydrostratigraphic layers: (i) the vadose zone, (ii) a layer with well-developed macropores at a depth of 1.5-4 m and (iii) an aquitard layer at a depth of 4-15 m. The temporal head fluctuations, the high K values of the second layer (>170 m d-1), and the large volume of water flowing into and out of the two subaquifers during large-scale field experiments all attest to excellent connectivity with the waterways. These results support the concept of critical source area which claims that most of the P loss in a catchment derives from small areas in which specific P release and transport mechanisms coincide with high connectivity. We conclude that the high connectivity of this Mediterranean altered wetland to waterways, coupled with the high P release that has occurred in recent years following soil flooding, provides the loading mechanism that partially explains the observed P increase in the Jordan River.

Original languageAmerican English
Pages (from-to)333-349
Number of pages17
JournalJournal of Hydrology
Volume349
Issue number3-4
DOIs
StatePublished - 1 Feb 2008

Bibliographical note

Funding Information:
This paper is dedicated to the memory of Prof. Ronit Nativ, whose experience and knowledge helped us with this issue and much more. The work was partly supported by a Grant from the Israeli Water Commission, EU project PROWATER, EVK1-CT1999-00036, and by the GLOWA-Jordan River Project funded by the German Ministry of Science and Education (BMBF), in collaboration with the Israeli Ministry of Science and Technology (MOST).

Keywords

  • Altered wetland
  • Connectivity
  • Critical source area
  • Peat
  • Phosphorus

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