1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology

Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)

EEZA-CSIC (EEZA-CSIC) - Spain

Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)

Consejería de Agricultura y Agua Murcia (CARM) - Spain

Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)

1.3 Conditions regarding the use of data documented through WOCAT

When were the data compiled (in the field)?

12/06/2008

The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:

Yes

2.1 Short description of the Technology

Definition of the Technology:

Water harvesting from intermittent streams towards nearby fields and terraces during runoff events.

2.2 Detailed description of the Technology

Description:

Water shortage is one of the most limiting factors for sustainable agriculture in large parts of SE-Spain. Part of the solution of this problem may come from the restoration of traditional water harvesting structures. Many of these structures were widely used in SE-Spain already during Arab and Roman times, and are also widespread in N-Africa and the Middle East. However, nowadays in Spain many of them are abandoned and forgotten. Here, we describe the technology of a small earthen- or stone- built bund that diverts flood water from intermittent streams towards cultivated fields with almond orchards and/or cereals. The diverted water will temporarily flood the fields and provide the crops with water. Depending on the slope gradient and the amount of water to be harvested, the fields are organised as single terraces, or as a staircase of terraces. On fields with gradients above ~3%, terraces are necessary to reduce the gradient and to retain the floodwater as long as possible. Water is diverted from one terrace to the next through small spillways in the terrace. The spillways can best be fortified with stones to prevent bank gully formation. The extra input of surface water can double the almond yield. The use of these water harvesting structures is only possible under certain environmental and topographic conditions. The cultivated fields should be at a relatively short distance from an intermittent stream (<~50m), and the stream should have a sufficiently large upstream contributing area to provide significant amounts of runoff water during rainfall events. With these systems, water can be harvested up to 8 times per year, mostly in spring and autumn during high intensity rainfall events. A well designed Boquera system may provide up to 550 mm of additional water, in areas with an average annual rainfall of 300 m.

Purpose of the Technology: The goal of this technology is to increase crop yield. In addition, these structures help to reduce the intensity of floods and reduce the damage caused by them by reducing runoff volume in intermittent streams.

Establishment / maintenance activities and inputs: Water harvesting requires the identification of a suitable location for the construction of a diversion structure. This requires assessment of expected water inflow, which can usually be based on simple field observation during rainfall events and based on local knowledge of land users. It is, however, important to consider whether there are activities upstream that possibly affect the water quality (e.g. farm animals) and to assess the implications the water harvesting might have downstream. Permission is required from the water authorities to construct any type of water harvesting structure. Such structures are built by creating a small bund (<1m height) in the centre or to the side of a stream. Depending on the size, the bund can be built with a shovel or a tractor. The water harvesting structure will require control and some maintenance after each important runoff event. When strengthened with concrete, maintenance will be reduced to approximately once every 5 years.

Natural / human environment: Soils are mostly of shallow to medium depth (20-60 cm), and slopes are gentle to moderate (5-15%). The climate is semi-arid with a mean annual rainfall around 300 mm. Droughts, centred in summer commonly last for more than 4-5 months. Annual potential evapotranspiration rates larger than 1000 mm are common.

2.3 Photos of the Technology

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment

2.6 Date of implementation

If precise year is not known, indicate approximate date:

• more than 50 years ago (traditional)

2.7 Introduction of the Technology

Specify how the Technology was introduced:

• as part of a traditional system (> 50 years)

Comments (type of project, etc.):

Most of the water harvesting structures are already much older than 50 years and originate even from Roman or Arab times.

3.2 Current land use type(s) where the Technology is applied

Comments:

Major land use problems (compiler’s opinion): There is a lack of water for irrigation of crops limiting the crop types that can be planted as well as the crop yield of dryland farming. A lack of water availability seriously limits the production potential of the soil and results in a low vegetation/crop cover. The relatively high soil erosion rates cause various off-site related problems (i.e. flooding, reservoir siltation) and on-site problems (i.e. gully formation and loss of soil depth).

Major land use problems (land users’ perception): Lack of water for irrigation of crops limiting the crop types that can be planted as well as the crop yield of dryland farming.

Livestock is grazing on crop residues

3.3 Further information about land use

Water supply for the land on which the Technology is applied:

• rainfed

Number of growing seasons per year:

• 1

Specify:

Longest growing period in days: 220Longest growing period from month to month: november until June

3.4 SLM group to which the Technology belongs

• water harvesting

3.5 Spread of the Technology

Specify the spread of the Technology:

• evenly spread over an area

If the Technology is evenly spread over an area, indicate approximate area covered:

• < 0.1 km2 (10 ha)

Comments:

The exact area is not known. Traditionally the technology was common throughout the province of Murcia and the district of the upper Guadalentin, now most are abandoned and destroyed.

3.6 SLM measures comprising the Technology

Comments:

Main measures: structural measures

3.7 Main types of land degradation addressed by the Technology

Comments:

Main type of degradation addressed: Ha: aridification

Secondary types of degradation addressed: Wo: offsite degradation effects

Main causes of degradation: droughts (Dry periods and dry years require higher water availability)

Secondary causes of degradation: crop management (annual, perennial, tree/shrub) (Large areas without a protective vegetation cover cause increased runoff and erosion rates and facilitat flash floods), over abstraction / excessive withdrawal of water (for irrigation, industry, etc.) (Over-abstraction leads to a lowering of the water table. Therefore additional aquifer abstraction is not allowed by water authority.), Heavy / extreme rainfall (intensity/amounts) (Extreme rainfall causes flash floods with high water losses and low effectiveness for crop production.)

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:

• prevent land degradation
• reduce land degradation

Comments:

Main goals: prevention of land degradation, mitigation / reduction of land degradation

4.1 Technical drawing of the Technology

4.2 Technical specifications/ explanations of technical drawing

Sketch of a water harvesting structure consisting of an earthen- or stone- built dyke that diverts water into cultivated fields. Several terraces are present in the fields in order to reduce slope gradient and retain water longer within the fields to allow maximum infiltration. Depending on the expected inflow of water several spillways can be made per terrace to prevent excessive concentration of flow in each spillway.

Technical knowledge required for field staff / advisors: moderate (Selection of the proper location and assessment of up- and downstream linkages.)

Technical knowledge required for land users: low (Practical implementation of the water harvesting structure does not require a high level of knowledge)

Main technical functions: control of concentrated runoff: retain / trap, control of concentrated runoff: impede / retard, control of concentrated runoff: drain / divert, increase of infiltration, water harvesting / increase water supply

Secondary technical functions: increase of groundwater level / recharge of groundwater, water spreading

Spillway
Spacing between structures (m): 50
Depth of ditches/pits/dams (m): 0.5
Width of ditches/pits/dams (m): 1-3

Structural measure: water harvest dyke
Depth of ditches/pits/dams (m): <1
Width of ditches/pits/dams (m): <2
Length of ditches/pits/dams (m): <50

Construction material (earth): Soil from the stream banks is used to built the dyke and provide an opening into the cultivated fiel

Construction material (stone): Stones are used to fortify the dyke and spillways against the impact of flow.

Construction material (concrete): Potentially concrete is used to fortify the dyke and spillways against the impact of flow.

Specification of dams/ pans/ ponds: Capacity 5m3

Catchment area: >0.5km2m2

Beneficial area: 1-2 ham2

Slope of dam wall inside: 100%;
Slope of dam wall outside: 100%

Dimensions of spillways: 1-3m wide and <50 cm deep

4.3 General information regarding the calculation of inputs and costs

other/ national currency (specify):

EURO

Indicate exchange rate from USD to local currency (if relevant): 1 USD =:

0.63

4.4 Establishment activities

	Activity	Type of measure	Timing
1.	Construction of a dyke (dam)	Structural	summer or winter

4.5 Costs and inputs needed for establishment

	Specify input	Unit	Quantity	Costs per Unit	Total costs per input	% of costs borne by land users
Labour	Labour	5 meter dyke	1.0	150.0	150.0	100.0
Equipment	Machine use	5 meter dyke	1.0	350.0	350.0	100.0
Construction material	Concrete	5 meter dyke	1.0	400.0	400.0	100.0
Total costs for establishment of the Technology					900.0

Comments:

Duration of establishment phase: 1 month(s)

4.6 Maintenance/ recurrent activities

	Activity	Type of measure	Timing/ frequency
1.	restoration of the dyke	Structural	once in 5 yr (after important events)

4.7 Costs and inputs needed for maintenance/ recurrent activities (per year)

	Specify input	Unit	Quantity	Costs per Unit	Total costs per input	% of costs borne by land users
Labour	Labour	5 meter dyke	1.0	4.0	4.0	100.0
Equipment	Machine use	5 meter dyke	1.0	12.0	12.0	100.0
Construction material	Concrete	5 meter dyke	1.0	25.0	25.0	100.0
Total costs for maintenance of the Technology					41.0

Comments:

Machinery/ tools: For construction and maintenance of the dyke tractor or small bulldozer is required.

The costs were indicated assuming a length of the bund dimensions of 5*1*1 metres. Maintenance is required once every 5 years, so yearly costs are the total costs divided by 5 (Prices are for spring 2008).

4.8 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

Labour costs and price of concrete are the most determinate factors affecting the costs.

5.1 Climate

5.2 Topography

Indicate if the Technology is specifically applied in:

• concave situations

Comments and further specifications on topography:

Landforms: Valley floors (mostly concave slope section)

5.3 Soils

5.4 Water availability and quality

Comments and further specifications on water quality and quantity:

Ground water table: >50m (There is a lowering of groundwater table due to overexploitation for irrigation purposes)
Availability of surface water: Poor/none. Sporadically excess when there are flash floods during extreme rainfall events
Water quality (untreated) For agricultural use only (irrigation)(groundwater)

5.5 Biodiversity

5.6 Characteristics of land users applying the Technology

Indicate other relevant characteristics of the land users:

Land users applying the Technology are mainly common / average land users
Difference in the involvement of women and men: Traditionally most agriculture is done by men in this region.
Population density: 10-50 persons/km2
Annual population growth: < 0.5%
15% of the land users are rich and own 20% of the land.
80% of the land users are average wealthy and own 75% of the land.
5% of the land users are poor and own 5% of the land.
Off-farm income specification: There is no difference in the ones who apply the technology and those who don’t. Most farmers do have an off-farm income for example from hunting, work in a factory, or office.

Market orientation: Commercial/market or mixed (subsistence and commercial)(some farmers are weekend or hobby farmers and not market oriented)

5.7 Average area of land owned or leased by land users applying the Technology

5.8 Land ownership, land use rights, and water use rights

Land ownership:

• state
• individual, titled

Land use rights:

• communal (organized)
• individual

Water use rights:

• communal (organized)
• individual

Comments:

Most land is privately owned. The streams are not privately owned. Therefore permits are required to construct a water harvesting structure. Some shrubland or forest is state property. Water rights are provided and controlled by the Water authority of the Segura river basin (CHS).

5.9 Access to services and infrastructure

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

Water availability and quality

Income and costs

Socio-cultural impacts

Ecological impacts

Water cycle/ runoff

Soil

6.2 Off-site impacts the Technology has shown

6.3 Exposure and sensitivity of the Technology to gradual climate change and climate-related extremes/ disasters (as perceived by land users)

Gradual climate change

Gradual climate change

	Season	Type of climatic change/ extreme	How does the Technology cope with it?
annual temperature		increase	well

Climate-related extremes (disasters)

Meteorological disasters

	How does the Technology cope with it?
local rainstorm	not well
local windstorm	well

Climatological disasters

	How does the Technology cope with it?
drought	well

Hydrological disasters

	How does the Technology cope with it?
general (river) flood	not well

Other climate-related consequences

Other climate-related consequences

	How does the Technology cope with it?
reduced growing period	well

Comments:

The crop type is sensitive to changes in water availability under the semi arid conditions.

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?

Comments:

Implementation of the technology is relatively expensive. Once installed, maintenance is not expensive and pays off because of higher productivity.

6.5 Adoption of the Technology

Of all those who have adopted the Technology, how many have did so spontaneously, i.e. without receiving any material incentives/ payments?

• 90-100%

Comments:

100% of land user families have adopted the Technology without any external material support

There is no trend towards spontaneous adoption of the Technology

Comments on adoption trend: Much of this knowledge is forgotten and not applied or maintained anymore.

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
The extra input of free water allows higher crop productivity.

Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
This technology is very effective at increasing water available for crop production and so increasing crop yield and farm income How can they be sustained / enhanced? Temporarily store the harvested water in a cistern to be used for irrigation using drip irrigation when most needed.
The technology takes advantage of floodwater that is otherwise lost because of the erratic character and short duration of flow How can they be sustained / enhanced? Finding the optimal location for the water harvesting structures using a modelling approach

6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

Weaknesses/ disadvantages/ risks in the land user’s view	How can they be overcome?
Farmers consider it relatively expensive to implement and there is no guarantee for water as this depends on the rainfall events.	Subsidies might help to install these structures where feasible. Therefore, good assessments of expected water inflow volumes are required before construction

Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view	How can they be overcome?
The implementation costs are relatively high when the bunds are made of concrete	Use of cheap materials that are freely available (stones from the fields). However, it is important to make the structure as resistant as possible against flood events.
The water provided by these techniques is mostly interesting for small- and medium- scale rainfed farming. Intensively irrigated farming requires more water and a guarantee for water independently of flood events	Intensively irrigated farming might use this technology as an additional source of water and may store the harvested water in a cistern for use when needed.

7.2 References to available publications

Title, author, year, ISBN:

rot, E., van Wesemael, B., Benet, A.S. and House, M.A., 2008. Water harvesting potential in function of hillslope characteristics: A case study from the Sierra de Gador Journal of Arid Environments 72(7):1213-1231

Available from where? Costs?

Internet

Title, author, year, ISBN:

Giráldez, J.V., Ayuso, J.L., Garcia, A., López, J.G. and Roldán, J., 1988. Water harvesting strategies in the semiarid climate of southeastern Spain. Agricultural Water Management, 14(1-4): 253-263.

Available from where? Costs?

Internet

Title, author, year, ISBN:

Hooke, J.M. and Mant, J.M., 2002. Floodwater use and management strategies in valleys of southeast Spain. Land Degradation & Development, 13(2): 165-175.

Available from where? Costs?

Internet

Title, author, year, ISBN:

López-Gálvez, J. and Losada, A., 1998. EVOLUCIÓN DE TÉCNICAS DE RIEGO EN EL SUDESTE DE ESPAÑA. Ingeniería del Agua, 5(3): 41-50.

Available from where? Costs?

Internet

Title, author, year, ISBN:

Nasri, S., Albergel, J., Cudennec, C. and Berndtsson, R., 2004. Hydrological processes in macrocatchment water harvestingin the arid region of Tunisia: the traditional system of tabias. Hydrological Sciences-Journal, 49(2): 261-272.

Available from where? Costs?

Internet

Title, author, year, ISBN:

van Wesemael, B., et al., 1998. Collection and storage of runoff from hillslopes in a semi-arid environment: geomorphic and hydrologic aspects of the aljibe system in Almeria (Spain). Journal of Arid Environments 40(1):1-14

Available from where? Costs?

Internet

Title, author, year, ISBN:

Greenpeace, 2007. El negocio del agua en la cuenca del Segura, Greenpeace.

Available from where? Costs?

www.greenpeace.es