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Constraints and limitations.  45% - 54% of Crops area, (0.66 M ha)  Two seasonal rainfall (spring, Autumn)  Long dry season (nearly six months)  All.

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Presentation on theme: "Constraints and limitations.  45% - 54% of Crops area, (0.66 M ha)  Two seasonal rainfall (spring, Autumn)  Long dry season (nearly six months)  All."— Presentation transcript:

1 Constraints and limitations

2  45% - 54% of Crops area, (0.66 M ha)  Two seasonal rainfall (spring, Autumn)  Long dry season (nearly six months)  All rainfed areas contain one component or more of traditional water harvesting techniques.

3 Changes in land use  Disturbances in run off areas  Population Residence expanded into rainfed area (rural areas)  Absence of zoning for agriculture Land  Terraces degradation -Land Abandonment Effect of climate change  Starting as early as 70’s with limited effect on low rainfall areas in highland and increases over the last decades: - high intensity, short duration, on small area - Rainfall occurred during dry season (Jahr), affect planting date and plant growth

4  27% - 35% of cropped areas (0.41 – 0.45 M ha)  Over the last three decades, wells depth Increases : - ten and twenty folds (40 – 400, 800 m), Sanaa Basin, and in costal areas increases five folds (10 – 50, 100 m), (sea water intrusion) - Now, farmers grow veg. and some fruits using saline water (4 ds/m).  Cost of water abstraction increases nearly four times for the same depth.

5  7.2% - 16% of cropped area (0.09 -0.24 M ha)  Water allocation according to customary rules, less conflicts  Increases in size of run off produced in urban areas but with various level of contamination  Change in land use, transform the absorbing zone of run off to produce zone mostly in the intermountain plains (sanaa, Jahran, …. )

6 Controlled irrigation systems  Dams, diversion structures in the western and southern coastal areas.  2.8% - 5.4 % of cropped area 60,000 ha  Protection of irrigated area and regulate floods.  Eliminate the need of annual consruction of traditonal deflectors Main Problems  Sedimentation  Cost of operation and maintenance  Conflict about water allocation between up streams and down stream beneficiaries

7 Rainfall, Groundwater, Floods

8  2.% - 2.75 %, of cropped area  High discharges occur during rainy season and decreases in dry season;  Discharges vary from one liter/sec in the Yemen Volcanic Rocks to nearly 600 L/s in the Mesozoic rocks in Wadi Surdud.  Water allocation, conducted according to customary rules; less conflict than sayl allocation.  Priority for water use is given to domestics usages.  Potential for improvements (storage and distribution canals)

9  Aquifers Depletion  Failure of local authority and related organizations to enforce water law and by-law which regulate water abstraction and wells drilling.  change in land use: population expanded over agriculture land.  Changing up stream rainfed area into irrigated ( well drilling, reservoirs), affected down streams users (dry wadi)  Effect of climate changes: Rainfall pattern, date of planting as related to moisture availability and growth periods.  Irrigation using contaminated or untreated waste water as an alternative to water scarcity.  Growing crops with low economic values


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