{{Short description|Bituminous face rockfill dam in Keserwan District, Lebanon}} {{Infobox dam | name = Faraya-Chabrouh Dam | image = Chabrouh dam with context.jpg | image_caption = View of the Chabrouh Dam reservoir and surrounding karstic terrain | name_official = Chabrouh Dam | country = Lebanon | location = Faraya, Keserwan District, Mount Lebanon Governorate | coordinates = {{coord|34|01|49|N|35|50|07|E|region:LB_type:landmark|display=inline,title}} | status = Operational | construction_began = 2002 | opening = 2007 | cost = Approx. US$85 million | builder = Andrade Gutierrez (Brazil) & Mouawad-Edde (Lebanon) consortium | owner = Ministry of Energy and Water | operator = Beirut and Mount Lebanon Water Establishment | dam_type = Bituminous face rockfill dam (BFRD) | dam_height = {{convert|65|m|ft|0}} | dam_length = {{convert|470|m|ft|0}} | dam_width_crest = {{convert|10|m|ft|0}} | dam_width_base = {{convert|200|m|ft|0}} | dam_elevation_crest = {{convert|1618|m|ft|0}} | dam_volume = {{convert|1550000|m3|cuyd|0}} | res_name = Chabrouh Reservoir | res_capacity_total = {{convert|9000000|m3|acre.ft|0}} | res_max_length = {{convert|1300|m|ft|0}} | res_capacity_active = {{convert|8000000|m3|acre.ft|0}} | spillway_count = 1 morning-glory ("tulip") overflow shaft spillway | spillway_capacity = {{convert|180|m3/s|cuft/s|0}} }}
The '''Faraya-Chabrouh Dam''' (commonly referred to as the '''Chabrouh Dam''') is a high-altitude bituminous face rockfill dam (BFRD) situated on the Wadi Chabrouh torrent in the upper reaches of the Keserwan District, Mount Lebanon Governorate, Lebanon. Located at an elevation of approximately 1,600 meters above sea level and roughly 40 kilometers northeast of the capital city of Beirut, the civil engineering asset serves as a critical infrastructure node in managing Lebanon's asymmetric seasonal water resources.
Inaugurated in 2007, the dam represents the second-largest reservoir facility in Lebanon. It was specifically engineered to capture seasonal alpine snowmelt and high-altitude precipitation during the winter and spring cycles, conserving water to mitigate severe municipal and agricultural deficits during the arid summer and autumn months. The reservoir provides treated potable water to an estimated 250,000 residents across the Keserwan region, balancing water security against complex regional hydrogeological and environmental challenges.<ref name="faraya_municipality"/><ref name="fanack"/>
== Historical Context and Project Genesis == The management of hydraulic infrastructure remains a cornerstone of national security and public health in post-civil war Lebanon. Preliminary topographical and hydrological feasibility studies aiming to exploit the steep, narrow gorge of Wadi Chabrouh were initially conducted by state engineering consultants in 1979.<ref name="libanconsult_news"/> Due to socio-political instability, the project was shelved until 1999, when it was formally integrated into a national master plan by the Ministry of Energy and Water to modernize surface storage assets and build climate resilience.<ref name="libanconsult_dams"/>
The administrative and structural development of the project was executed in close coordination with the Faraya Municipality.<ref name="faraya_municipality"/> Construction commenced in 2002 and concluded with the official impoundment and inauguration ceremonies in 2007. The project was executed by an international joint venture comprising the Brazilian civil engineering conglomerate Andrade Gutierrez and the prominent Lebanese contracting firm Mouawad-Edde s.a.r.l.<ref name="mouawad"/>
To optimize logistical execution, the overall project lifecycle was segmented into three distinct contractual lots: * '''Lot 1 (Dam Structure):''' Excavation, structural filling, and placement of the upstream sealing slab.<ref name="mouawad"/> * '''Lot 2 (Adduction Pipeline):''' Construction of a 5,190-meter-long gravity-fed adduction line linking the high-altitude Nabaa El Laban spring directly to the reservoir basin.<ref name="faraya_municipality"/> * '''Lot 3 (Water Treatment Infrastructure):''' Engineering a dedicated downstream filtration and chlorination plant to process raw reservoir water for municipal distribution.<ref name="libanconsult_dams"/>
== Technical Architecture and Design ==
=== Structural Profile === The Chabrouh Dam was engineered as a bituminous face rockfill dam (BFRD), a structural morphology selected for its inherent flexibility, stability against local seismic faults, and capacity to withstand extreme high-altitude freeze-thaw cycles without fracturing.<ref name="faraya_municipality"/> The main embankment features a maximum height of 63 to 65 meters from the foundational bedrock, spanning a crest length of 470 meters and a crest width of 10 meters.<ref name="faraya_municipality"/> The base width extends to approximately 200 meters at its widest foundational footprint.
The structural matrix consists of over 1.55 million cubic meters of zoned hard limestone rockfill, carefully graded and compacted. Material was sourced from two primary quarries located within a 5-kilometer radius of the construction site.<ref name="mouawad"/> The upstream face of the embankment is sealed by a 37,000-square-meter bituminous concrete liner. This 22-centimeter-thick impermeable barrier is constructed using multi-layered technology: a 10 cm thick base binder layer topped with two separate 6 cm layers of dense asphaltic concrete designed to dynamically adjust to micro-settlements within the underlying rockfill material.<ref name="faraya_municipality"/>
=== Hydrological and Hydraulic Systems === The catch basin of the reservoir relies primarily on targeted inflows from the Nabaa El Laban spring, capturing substantial runoff from the surrounding Mount Lebanon range to establish a gross storage capacity of approximately 8 to 9 million cubic meters (MCM).<ref name="fanack"/>
The dam’s hydraulic safety features include a specialized morning-glory, or "tulip," overflow shaft spillway. The spillway structure measures 11.2 meters in diameter at its lip and drops into a 50-meter-deep vertical shaft, which is connected to a 410-meter-long concrete-lined diversion tunnel.<ref name="faraya_municipality"/> This system is capable of safely discharging up to 180 cubic meters per second (m³/s) of flash flood water downstream, preventing catastrophic overtopping of the main rockfill embankment. Primary water draws for municipal processing are regulated by a 7.2-meter-diameter intake tower fitted with an 800 mm diameter adduction pipe and specialized butterfly valves.<ref name="faraya_municipality"/>
== Hydrogeological Challenges and Seepage == Despite its strategic importance, the operation of the Chabrouh Dam has been complicated by the karstic hydrogeology of the Mount Lebanon region. Approximately 65% of Lebanon’s surface terrain consists of carbonate rocks (limestone and dolomite) highly susceptible to chemical weathering, which forms subterranean conduits, caves, and sinkholes.<ref name="researchgate"/>
Comprehensive geological tracing and isotopic evaluations conducted post-impoundment identified a significant subsurface leakage bypass migrating through the right embankment abutment. Subsurface water losses through the karstic channels of the adjacent Qana Plateau have been documented between 22,000 and 33,000 cubic meters per day.<ref name="legalagenda"/> Engineering data has confirmed that this escaping volume does not represent a complete loss to the national water balance; rather, the leaked water re-emerges downstream, increasing the natural discharge of the nearby Qana and Hadid springs by up to 89% following full reservoir impoundment.<ref name="researchgate"/> Remedial grouting curtains have been intermittently injected into the bedrock foundations to control the rate of karstic seepage.
== Environmental Regulations and Watershed Protection ==
=== The 2025 Access Ban === In August 2025, the Ministry of Energy and Water, acting on technical directives from the Faraya Municipality, issued an absolute prohibition on all public, mechanical, and recreational activities within the immediate perimeter of the Chabrouh Dam reservoir.<ref name="olj_ban"/>
The regulatory intervention was prompted by a specialized multi-disciplinary scientific study assessing water quality risks. The report highlighted severe ecological and sanitary vulnerabilities, warning that motorized watercraft (such as jet-skis) caused petroleum hydrocarbon pollution and heavy acoustic disruptions. Furthermore, high-velocity mechanical activities triggered severe water turbulence that resuspended fine bottom sediments—an operational risk noted by independent engineering consultants as early as 2013.<ref name="olj_ban"/>
Because the immediate watershed lacks localized sanitary, solid waste, and stormwater management infrastructure capable of supporting heavy tourist crowds, strict containment became necessary. This urgency was compounded by acute regional drought cycles during the 2024–2025 winter season, which dropped the reservoir volume to roughly 30% of its active capacity.<ref name="olj_ban"/> State authorities and municipal representatives entered into exploratory talks with international development donors to design low-impact, non-motorized eco-tourism initiatives (such as kayaking and rowing), but preserving raw water standards for the 250,000 municipal consumers remains the definitive priority.<ref name="olj_ban"/>
=== Ecological Reforestation === To counter soil erosion along the barren slopes encircling the reservoir, long-term ecological restoration programs have been implemented by non-governmental organizations, notably Jouzour Loubnan.<ref name="jouzour"/> These initiatives focus on planting native cedar and juniper species within dedicated plots. These areas are strictly protected from livestock grazing to establish a natural vegetative buffer zone, stabilizing peripheral topsoil and reducing sediment deposition within the reservoir basin.
== See also == * List of dams in Lebanon * Water supply and sanitation in Lebanon * Geography of Lebanon
== References == {{Reflist|refs= <ref name="fanack">{{cite web |title=Water Infrastructure in Lebanon |url=https://water.fanack.com/lebanon/water-infrastructure-in-lebanon/ |website=Fanack Water |access-date=May 16, 2026}}</ref>
<ref name="libanconsult_news">{{cite web |title=Liban Consult AGM History and News |url=https://libanconsult.com/en/home/12-university-news |website=Liban Consult |access-date=May 16, 2026}}</ref>
<ref name="libanconsult_dams">{{cite web |title=Dams and Hydraulic Portfolio |url=https://www.libanconsult.com/en/activities/dams |website=LibanConsult AGM |access-date=May 16, 2026}}</ref>
<ref name="faraya_municipality">{{cite web |title=Chabrouh Dam Official Profile |url=https://faraya.gov.lb/chabrouh-dam/ |website=Faraya Municipality Official Portal |access-date=May 16, 2026}}</ref>
<ref name="mouawad">{{cite web |title=Chabrouh Dam Project Specifications |url=https://www.mouawad-edde.com/ |website=MOUAWAD - EDDE s.a.r.l. |access-date=May 16, 2026}}</ref>
<ref name="researchgate">{{cite journal |last1=El-Hajj |first1=A. |title=Understanding the Leaks in Chabrouh Dam Through Detailed Hydrogeological Analysis of the Qana Plateau, Lebanon |journal=ResearchGate |url=https://www.researchgate.net/publication/226280611 |access-date=May 16, 2026}}</ref>
<ref name="legalagenda">{{cite web |last1=Ghattas |first1=M. |title=Lebanon Dam Business: Destroying the Environment and Squandering Public Funds |url=https://english.legal-agenda.com/lebanon-dam-business-destroying-the-environment-and-squandering-public-funds/ |website=The Legal Agenda |access-date=May 16, 2026}}</ref>
<ref name="olj_ban">{{cite news |title=Saddi bans activities at Chabrouh Dam to protect water quality |url=https://today.lorientlejour.com/article/1474712/saddi-bans-activities-at-chabrouh-dam-to-protect-water-quality.html |newspaper=L'Orient Today |date=August 23, 2025 |access-date=May 16, 2026}}</ref>
<ref name="jouzour">{{cite web |title=Chabrouh – Faraya Reforestation Site |url=https://www.jouzourloubnan.org/plantation-sites-mountlebanon/2019/11/5/chabrouh-faraya |website=Jouzour Loubnan |access-date=May 16, 2026}}</ref> }}
== External links == * [https://faraya.gov.lb/chabrouh-dam/ Faraya Municipality Official Website - Chabrouh Dam Portal] * [https://www.mouawad-edde.com/ Mouawad-Edde Civil Engineering Portfolio]
Category:Dams in Lebanon Category:Keserwan District Category:Buildings and structures completed in 2007