III. Wadi Floodwater Harvesting
This system depends on harvesting water from wadis. Water flow in the wadis is seasonal, erratic, and occasionally torrential. Several methods are used to harvest water from the wadi which depends on slowing water flow during peak discharge to allow water infiltration and divert water flow to fields or cisterns.
Jessour(pl.), Jisr (sing.).
Wall built across step wadi (e.g., in Tunisia). Spillways may be used.
Wadi cross walls, dams, dykes (Marbid, Arabic, Yemen),
Stone wall constructed across gentle-sloping wadi bed. Dams are rarely above one meter.
A series of check dams may be used to slow water down and increase infiltration, or for water storage in cisterns or tanks.
A series of dams is constructed in the wadi bed to direct water for cultivation on wadi bank terraces.
Wadi High Dams & Reservoirs
High dams more than 10 meters in height have been constructed since Antiquity. Among the oldest high dams is Sadd el-Kafara in Wadi Garawi, Egypt, the Sadd at Jawa, Jordan, and the Ma'arib dam in Yemen.
Sadd el-Kafara, Wadi Garawi, Egypt (photo Fekri Hassan)
Tabia: Large (semicircular) bunds, Rabat
Term used in Tunisia referring to the use of large earthen bunds in circular, trapezoidal or V-shape, about 10-100 meters in length and 1-2m in height.
They are staggered facing upslope.
Water Diversion Levee & Dam (Water Speeding System)
Water in a wadi is diverted by a dam or dyke to raise its level so that it can be channelled to the banks of the wadi. A levee is used on the side of the wadi to direct the water.
Flat area of wadi where water collects.
Large basins, often at high elevations where water is collected behind dams.
Waterfall Harvesting Cistern
A cistern constructed to receive water cascading from a waterfall.
IV. River Floodwater
Stream Irrigation System
An irrigation system that makes use of water flowing in a natural stream
Basin Irrigation (dykes and levees)
Water is diverted from the river into a feeder canal. Artificial basins are created by a system of levees (a high embankment parallel to the channel) and a series of cross-dykes. The embankment next to the Nile is called Tarad. The cross dykes are called "Salayib" (pl., sing. Saliba). Water is drained back into the river through a drainage canal. Each group of five or six basins constitutes a chain (Silsila). Canals leading to lower parts of the basins are called syialat (pl., siyala, sing.). The canal ?????
Water gates constructed to regulate the flow of water in a stream. They are also used as bridges.
Hod zar'. Small farming basins
Small basins for planting vegetables and other crops are created by constructing low ridges. The basins are fed by water runnels.
Wells may be dug to take advantage of water seepage from irrigation canals and the main streams in areas outside those supplied by canals or to ensure supply of water regardless of the water level in a canal. In the Faiyum, Egypt, a water well dating to the Roman period was found at Karanis, Faiyum Oasis.
V. Groundwater Harvesting
SpringKhazan, Majahir(Syria),'Ain (Egypt)
Water tank to hold spring water.
A pit for collecting water from sand above an impermeable layer.
Drip water Harvesting
Water dripping from seepage in a cave is collected in storage pits. Common in Karstic areas where limestone has dissolved to form sinkholes, solution fissures, subterranean tunnels, caves, and other solution features.
Open galleries or aqueducts
Open, surface channel used to convey and distribute water (photo F. Hassan, Dab'a, Egypt)
Underground Qanats(Qanwat Romani, pl.), Khettara orKahariz (Iraq, Iran, Afghanistan, Pakistan)
A subterranean tunnel connected to a well used to tap and convey water from an aquifer over a fairly long distance down a gentle slope to be used for irrigation and domestic functions. Storage tanks may be used. The first intake well is called a "mother well". Shafts or wells spaced within tens of meters of one another serve as air shafts and provide access for maintenance. These were already highly developed in western Iran, northern Mesopotamia and eastern Turkey at least 2800 years ago. The system with modifications and regional variants is known from later periods in Greece, Rome, and the under the Arabs in North Africa. The qanats of southern Algeria and southern Morocco are the best developed outside southwest Asia. Introduced into Spain by the Arabs the qanats spread subsequently to Mexico, Peru and Chile. The qanats are also known from the Arabian Peninsula where they are called Aflaj, and are reported from farther east in China.
Coastal perched water qanats (Egypt)
Water is collected from the freshwater layer perched on top of sea water in subterranean tunnels a few kilometres long with manholes spaced about 20 meters apart. The manholes are excavated in porous limestone underlying coastal dune sand. (photos by F. Hassan, Matrouh, Egypt)
Artificial basins, Afreg (Algeria)
An artificial basin is excavated in a dune field reaching close to the shallow water table supplied by local rainfall.
Shallow water wells (Jilban, Iraq)
Shallow well to collect water from sand in a wadi bed
Instead of lifting water by a bucket (with or without a pulley), these shallow groundwater tables are reached either by a ramp which could be also used by animals, or by a staircase, which may be constructed at several levels.
A well drilled to reach a ground water table. Water rises to the surface as a result of an internal hydrostatic pressure.
Artesian well, Egypt (photo F. Hassan)
Agroundwater cistern excavated below ground to harvest water seepage from a shallow water table.
VI. Moisture Harvesting
Moisture Harvesting Mounds
Water harvesting from the condensation of air moisture using a mound of stones. Water drips from the mound into a pit below it.
Moisture Condensation Canopy
A canopy is placed on top of a water tight hole to collect condensed water. Alternatively a plastic sheet with a stone at the center may be placed over a hole where a receptacle is situated below the stone. Overnight dew drips into the receptacle.
Stone slab moisture capture
Arrangement of stone slabs to capture and channel moisture in the air through condensation to the ground.
VII. Snow Water Harvesting
Snow harvesting enclosures: snow captured in low wall enclosures associated with pastoral settlements and animal enclosures (Photo F. Hassan, Morocco).
Snow meltwater is harvested in reservoirs using dams (Photos F. Hassan, Morocco).
Water Transport and Distribution
Mesqa (Egypt, ditch or irrigation canal) , Saqqia (Morocco)(canal?)
(Photo F. Hassan, Adrar, Algeria)
A ditch or runnel used to convery water from source to landuse area.
Qanat comb distributary system
System used to allocate shares of water for distribution to users (Photo. F. Hassan, Adrar)
Aqueducts are narrow runnels used to convey water. Where water crosses a low area, structures may be constructed allowing water to flow in a narrow channel at the top of the structures.
Terracotta pipe aqueducts
Terracotta pipes were used in Crete and Jordan in ancient times to transport water. They become widely used under the Romans (Petra, Photo U. Bellwald, PNT, Jordan