Innovative Adaptation Pilots:

Lebanon

Managed Aquifer Recharge as an integrated water resource management approach for preventing sea water intrusion in Hazmieh (Beirut area)

 

Background

Lebanon’s per capita water resources are projected to decrease to 839 m3 in 2015 (Bassil 2010). Rapid and uncontrolled urban expansion over the past decades have led to a serious degradation of the environment and impaired water quality in much of the country. It is expected that the country will be unable to meet its local demand by 2025.

For meeting the future water demand, the national water strategy proposes to increase the renewable available water resources in 2035 by optimizing the use of surface water resources, using managed aquifer recharge (MAR) and increasing surface storage through dams and hill lakes.

Another concern is seawater intrusion near coastal areas that is fostered by overexploitation of coastal aquifers (Korfali & Jurdi, 2010). Due to high salinity concentrations, the groundwater has very limited use for domestic, industrial or agricultural purposes (Saadeh ,2008).

Climate change further exacerbates the pressure on water resources, with consensus opinion indicating mean temperature increases of 4°C and mean precipitation reductions reaching about 30% across MENA region by 2100. Daily, seasonal and interannual precipitation variability are also projected to increase. According to the Second National Communication (SNC) study, climate changes would adversely affect the renewable water resources available per capita and increase water stress.

 

Project rationale

Lebanon is already witnessing signs of decreasing precipitation and increasing drought and desertification. This is the result of research done by studying the historical climate data. Very little climate modeling work has been focused specifically on Lebanon. Some of the modeling results illustrate that surplus water, which ultimately produces runoff or percolates and reaches water bodies, is reduced by 11–34 mm/year (3.5–11% ) for Ksara area in Bekaa, and 21– 49 mm/ year (6.5–15% ) for Beirut (Bou-Zeid & El-Fadel 2002). Since surplus is the main source of water for surface water bodies and groundwater aquifers, this reduction will directly influence available water resources in the country. These potential impacts might be exacerbated by the alteration in flow regimes in Lebanese rivers that are fed by snowmelt. Based on the assumption that river peak flow would shift from the end of April to the end of February, river flows would increase between December and February and will dramatically decrease during periods of high water demand season.

The national water strategy considers managed groundwater recharge as one of the measures to increase groundwater resources (up to 0.2Bm3 is estimated to be increased by 2020) as well as an adaptation measure to climate change. Currently about 0.4Bm3 run-off is lost to the sea every year and it is projected that this amount increases under climate change conditions (increasing of storm events). This water can be potentially used for groundwater recharge in coastal aquifers which are witnessing signs of water quality deterioration due to sea water intrusion. The ground recharge also improves the adaptability of the water resources system to the natural variability of climate patterns. Thus, the adaptation measure shows significant benefits regardless of climate change impacts (no-regret option).

The projected feasibility study shall develop a suitable solution for managing aquifer recharge in order to improve the groundwater quality/reduce salinity in Hazmieh area. By using an appropriate methodology such as an integrated water resources management approach (IWRM), further sea water intrusion shall be prevented. The quantitative analysis of available water sources for recharge is crucial as water is considered too scarce in the area to be diverted from existing demands. Storm water of wadis and river peak flows and harvested rainwater from roof and streets (Beirut has an average annual precipitation of 800mm) can be considered as alternative water sources.

 

Objective

Conducting a feasibility study to evaluate the potential of implementing managed aquifer recharge using an appropriate integrated water resources management approach in order to improve the groundwater quality regarding salinity in the Hazmieh area, Beirut .

 

Expected outputs

  • Available studies and data related to manage aquifer recharge in Lebanon are evaluated.
  • The present impact of sea water intrusion on groundwater quality in the study area is assessed.
  • A remediation process for improving groundwater quality in regard to salinity in the study area using an integrated water resources management approach is defined.
  • Implementable measures and techniques for improving groundwater quality in the study area are proposed.

Further Information:

Case Study ACCWaM Lebanon

 

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