1.2 参与该技术评估和文件编制的资源人员和机构的联系方式

有助于对技术进行记录/评估的项目名称（如相关）

Book project: SLM in Practice - Guidelines and Best Practices for Sub-Saharan Africa (SLM in Practice)

有助于对技术进行记录/评估的机构名称（如相关）

UNESCO - IHE (UNESCO - IHE) - 荷兰

1.3 关于使用通过WOCAT记录的数据的条件

编制者和关键资源人员接受有关使用通过WOCAT记录数据的条件。:

是

2.1 技术简介

技术定义:

Spate irrigation is a traditional water diversion and spreading technology.

2.2 技术的详细说明

说明:

Spate irrigation has a long history in Eritrea and still forms the livelihood base for rural communities in arid lowlands of the country.

Purpose of the Technology: It is a traditional water diversion and spreading technique under which seasonal floods of short duration – springing from the rainfall-rich highlands – are diverted from ephemeral rivers (wadis) to irrigate cascades of leveled and bunded fields in the coastal plains.

Establishment / maintenance activities and inputs: The diversion structures include the following elements: (1) the ‘agim’, a temporary 3-4 m high river diversion structure on the low-flow side of the wadi, made from brushwood, tree trunks, earth, stones and/or boulders, erected to divert a large part of the flow during a spate flow to adjacent agricultural fields; (2) a primary, and several secondary, distribution canals; unlined, bordered by earthen embankments; convey and spread the floodwater to the irrigable fields; (3) the fields, rectangular shaped, of about 1–2 ha, separated by earthen bunds. Floodwater is distributed from field to field: when a field is completely flooded (to a depth of about 0.5 m), water is conveyed to the immediate downstream field by breaching one of the bunds. This process continues until all the water is used up. Arable fields need to be flooded several times. The water soaks deep into the soil profile (up to 2.4 m) and provides moisture sufficient for two or even three harvests: crop growth is entirely dependent on the residual soil moisture. The main crop grown is sorghum; maize is the next most important. Sedimentation is as important as water management: With each flood, soil is built up by depositing rich sediment on the fields. Due to the force of the floods, the diversion structures are frequently damaged and/or washed away. Reconstruction and maintenance are labour-intensive and require collective community action.

Natural / human environment: Elaborate local regulations, organization and cooperation at the community level are prerequisites for successful management of spate irrigation systems.

2.3 技术照片

2.5 已应用该技术的、本评估所涵盖的国家/地区/地点

2.6 实施日期

如果不知道确切的年份，请说明大概的日期:

• 50多年前（传统）

2.7 技术介绍

详细说明该技术是如何引入的:

• 作为传统系统的一部分（> 50 年）

注释（项目类型等）:

Spate irrigation is an indigenous technology, originally introduced from Yemen

3.1 该技术的主要目的

• 改良生产
• 减少、预防、恢复土地退化

3.2 应用该技术的当前土地利用类型

注释:

Livestock is grazing on crop residues

3.3 有关土地利用的更多信息

注释:

Water supply: post-flooding

3.4 该技术所属的SLM组

• 灌溉管理（包括供水、排水）
• 地表水管理（泉、河、湖、海）

3.5 技术传播

注释:

Total area covered by the SLM Technology is 160 m2.

Current spate irrigation area in Eritrea is 16’000 hectares. Potential area is estimated at 60’000–90’000 hectares.

3.6 包含该技术的可持续土地管理措施

注释:

Main measures: structural measures

4.1 该技术的技术图纸

4.2 技术规范/技术图纸说明

Cross section of an agim (top left); Components of a traditional spate irrigation system: (1) agim; (2) main distribution canal; (3) irrigated fields; (4) earthen embankments. Arrows indicate the water flow

Technical knowledge required for field staff / advisors: high

Technical knowledge required for land users: high

Main technical functions: control of concentrated runoff: drain / divert, increase of infiltration, water harvesting / increase water supply, water spreading

Diversion ditch/ drainage
Depth of ditches/pits/dams (m): 4.00

Construction material (earth): earth

Construction material (stone): stones

Construction material (wood): brushwood, tree trunks

4.4 技术建立活动

	活动	措施类型	时间
1.	Construction of diversion structure (agim)	结构性的	before rainy season
2.	Construction of main distribution canal	结构性的	before rainy season
3.	Construction of secondary distribution canals	结构性的	before rainy season
4.	Leveling of fields	结构性的	before rainy season
5.	Establish embankments around fields and within fields	结构性的	before rainy season

4.5 技术建立所需要的费用和投入

	对投入进行具体说明	单位	数量	单位成本	每项投入的总成本	土地使用者承担的成本%
劳动力	Labour	ha	1.0	24.0	24.0
设备	Animal traction	ha	1.0	36.0	36.0
技术建立所需总成本					60.0

4.6 维护/经常性活动

	活动	措施类型	时间/频率
1.	Reconstruction / repair of diversion structures (2-4 times / year; collective community action)	结构性的	2-4 times / year
2.	Desilting / repair of distribution canals	结构性的	annual
3.	Raising of bund heights due to silting up of fields	结构性的	annual
4.	Flood fields (community action, during highland rainy season: July-September). Most likely a field receives 3 irrigation turns, on a bi-weekly interval between any 2 turns	结构性的	rainy season (july-september)
5.	Soil tillage (15 cm deep; using oxen-drawn plough) to break capillary uplift of soil water and to create evaporation barrier	结构性的	end of flooding season

4.7 维护/经常性活动所需要的费用和投入（每年）

	对投入进行具体说明	单位	数量	单位成本	每项投入的总成本	土地使用者承担的成本%
劳动力	Labour	ha	1.0	24.0	24.0
设备	Animal traction	ha	1.0	36.0	36.0
技术维护所需总成本					60.0

注释:

Machinery/ tools: scouring and tillage implements, shovels

The costs were calculated per unit = 10 m long agim (1 m high, 3 m wide), constructed with mixed material (stones, earth, brushwood)

4.8 影响成本的最重要因素

描述影响成本的最决定性因素:

Data on labour inputs for construction/maintenance of canals and field bunds are not included, therefore not included in the tables above. Costs for agim reconstruction are 40% of establishment. Total maintenance costs depend on the number of reconstructions during normal spate season (2-4 times). The yearly cost (establishment and maintenance) reaches US$ 60-156.

5.1 气候

5.2 地形

关于地形的注释和进一步规范:

Altitudinal zone: 101-500 m a.s.l. (200 m.a.s.l.)

5.3 土壤

如有可能，附上完整的土壤描述或具体说明可用的信息，例如土壤类型、土壤酸碱度、阳离子交换能力、氮、盐度等。:

Soil texture is medium (loam to silt loams)
Soil fertility is very high (alluvial silts formed by annual sedimentation)
Soil drainage/infiltration is good

5.4 水资源可用性和质量

5.6 应用该技术的土地使用者的特征

说明土地使用者的其他有关特征:

Land users applying the Technology are mainly disadvantaged land users

Difference in the involvement of women and men: water management carried out communally, crop management individually

5.7 应用该技术的土地使用者拥有或租用的平均土地面积

5.8 土地所有权、土地使用权和水使用权

土地所有权:

• 州

土地使用权:

• 个人

6.1 该技术的现场影响

社会经济效应

生产

收入和成本

社会文化影响

生态影响

水循环/径流

土壤

6.3 技术对渐变气候以及与气候相关的极端情况/灾害的暴露和敏感性（土地使用者认为的极端情况/灾害）

渐变气候

渐变气候

	季节	气候变化/极端天气的类型	该技术是如何应对的？
年温度		增加	好

气候有关的极端情况（灾害）

气象灾害

	该技术是如何应对的？
局地暴雨	好
局地风暴	好

气候灾害

	该技术是如何应对的？
干旱	好

水文灾害

	该技术是如何应对的？
比较和缓的（河道）洪水	好

注释:

The technology is tolerant to climatic extremes (adapted to unpredictable heavy floods)

6.4 成本效益分析

注释:

no data

6.5 技术采用

注释:

There is a strong trend towards spontaneous adoption of the Technology

Comments on adoption trend: Spontaneous spread takes place throughout the lowlands. Current spate irrigation area in Eritrea is 16’000 hectares. Potential area is estimated at 60’000–90’000 hectares.

6.7 该技术的优点/长处/机会

编制者或其他关键资源人员认为的长处/优势/机会
Spate irrigation forms the livelihood base for rural communities in arid lowlands of the country

6.8 技术的弱点/缺点/风险及其克服方法

土地使用者认为的弱点/缺点/风险	如何克服它们？
Highly labour-intensive and time consuming maintenance; water diversion structures are frequently breached / washed away by heavy floods; canals are obstructed through deposition of boulders, gravel and coarse sediments.	To overcome all 3 problems, recommendations focus on building permanent flood diversion and distribution structures which:
Great demand for wood: huge numbers of trees are annually needed for (re-)constructing diversion structures	(1) withstand the force of heavy floods and divert the water effectively;
Irrigation efficiency is only about 20% because of the difficulty of controlling large amounts of water in a short period of time (and often at night) and because water is lost by percolation, seepage and evaporation	(2) eliminate the need to cut trees
	(3) reduce human and animal labour inputs
	(4) increase productivity; Lining the main canals with cements would reduce water loss by percolation and seepage. Proper leveling of basin fields helps to distribute the floodwater uniformly

7.2 参考可用出版物

标题、作者、年份、ISBN:

Abraham Mehari H, Van Steenbergen F, Verheijen O, Van Aarst S:Spate Irrigation, Livelihood Improvement and Adaptation to Climate Variability and Change

标题、作者、年份、ISBN:

Mehretab Tesfai Stroosnijder L:The Eritrean spate irrigation system

标题、作者、年份、ISBN:

Berhane Haile G, Van Steenbergen F: Agricultural Water Management in Ephemeral Rivers: Community Management in Spate Irrigation in Eritrea; in African Water Journal

7.3 链接到网络上可用的相关信息

标题/说明:

Abraham Mehari, Depeweg, H, Schultz B (2005): Hydraulic Performance Evaluation of The Wadi Laba Spate Irrigation Systemin Eritrea, in Irrigation and Drainage. 54: 389–406

URL:

www.interscience.wiley.com

标题/说明:

Berhane Haile G: Community Spate Irrigation in Bada, Eritrea n Mehretab Tesfai, Stroosnijder L (2000): The Eritrean spate irrigation system

URL:

linkinghub.elsevier.com/retrieve/pii/S0378377400001153