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Good practice Imported

Jessour Water-Harvesting Terraces — Reviving Mountain Runoff Capture in Tunisia's Matmata Hills

Tunisia · Mareth · See the Tunisia profile

Evidence: Quasi-experimental Top 40% 47/100 · Ask Evidence Copilot about this practice

Communities and Tunisia's Water and Soil Conservation Programme maintain jessour — stone terraces harvesting wadi runoff in the Matmata Mountains — with field data from 620 structures showing water savings equal to 500mm of rain from a 200mm annual average.

620
Jessour structures studied
~500mm/year vs ~200mm/year average
Effective annual water saving vs local rainfall average
~12,000 ha
National water-harvesting programme target area

Details

Maturity
Established
Promoter
Tunisia Ministry of Agriculture (Water and Soil Conservation Programme), with historical FAO technical assistance
Period
Traditional system, national programme active since 1990s; hydrological field monitoring 2018–2022
Keywords
water harvesting, soil conservation, mountain agriculture, olive and date farming

Context

Jessour and tabia are traditional water-harvesting structures built across steep wadis in Tunisia's arid Matmata Mountains and adjoining plains near Mareth, Gabès, where earthen or stone dykes trap runoff and sediment to create terraced, fertile micro-catchments for olive, fig and date trees.

Objectives

The practice, sustained for generations, is supported nationally through Tunisia's Water and Soil Conservation Programme (developed with historical FAO technical assistance) to extend water-harvesting works across comparable arid catchments.

Activities

Field research in the El-Jouabit micro-watershed evaluated 620 individual jessour structures using a water-balance model plus retention height, catchment surface and holding-capacity measurements, alongside paired soil-moisture monitoring stations installed upstream and downstream of a jesr (2018-2022, profiling to 1.25m depth).

Results

The paired monitoring confirmed measurable increases in retained soil water, and regional studies estimate jessour deliver water savings equivalent to roughly 500mm of rainfall per year in a zone averaging only about 200mm annually — a two-and-a-half-fold effective gain.

Conclusions

The hydrological evidence base (soil moisture, runoff capture) is the strongest part of this practice; economic and livelihood outcomes are less rigorously documented, and rural out-migration has led to abandonment of some terraces in less-accessible catchments.

Implementation
Indicative cost
Low (< €50k) — Low-cost traditional earthen/stone construction sustained by community labour; no monetary figures reported.
Time to results
Long (> 3 years) — Traditional practice sustained for generations; national programme active since the 1990s; hydrological field monitoring conducted 2018-2022.
Staffing & skills
Local farming communities (construction and maintenance of jessour), Tunisia Ministry of Agriculture — Water and Soil Conservation Programme, Historical FAO technical assistance

Conditions for success

  • Regular community desilting and wall maintenance
  • Continued rural population and labour availability to maintain terraces
  • National programme support for scaling comparable water-harvesting works

Common failure modes

  • Rural out-migration has led to abandonment of terraces in less-accessible catchments
  • Effectiveness depends heavily on rainfall variability

Where it fits

Governance type
community-managed with national programme support
Scale
watershed/local (620 structures studied in one micro-watershed)
Income level
lower-middle-income

Commonly funded by

National / regional programmes

Indicative funding routes for practices of this type — always check each programme's current calls and eligibility rules.

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Data sources

Where this practice's information was retrieved from, and when.

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