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Spate Irrigation [厄立特里亚]

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technologies_1333 - 厄立特里亚

完整性: 71%

1. 一般信息

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

关键资源人

SLM专业人员:

Abraham Mehari Haile

A.MehariHaile@unesco-ihe.org

UNESCO-IHE Institute for Water Education, Delft, The Netherlands

Westvest 7, 2611 AX Delft, Netherlands

荷兰

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。:

2. SLM技术的说明

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

国家:

厄立特里亚

区域/州/省:

Sheeb area, Eastern lowlands

有关地点的进一步说明:

Wadi Laba

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. SLM技术的分类

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

农田

农田

  • 一年一作
主要农作物(经济作物及粮食作物):

Major food crop: Sorghum, maïze

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

结构措施

结构措施

  • S3:分级沟渠、渠道、水道
注释:

Main measures: structural measures

4. 技术规范、实施活动、投入和成本

4.1 该技术的技术图纸

作者:

Mats Gurtner, Center for Development and Environment, University of Bern

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. 自然和人文环境

5.1 气候

年降雨量
  • < 250毫米
  • 251-500毫米
  • 501-750毫米
  • 751-1,000毫米
  • 1,001-1,500毫米
  • 1,501-2,000毫米
  • 2,001-3,000毫米
  • 3,001-4,000毫米
  • > 4,000毫米
农业气候带
  • 干旱

Thermal climate class: tropics

5.2 地形

平均坡度:
  • 水平(0-2%)
  • 缓降(3-5%)
  • 平缓(6-10%)
  • 滚坡(11-15%)
  • 崎岖(16-30%)
  • 陡峭(31-60%)
  • 非常陡峭(>60%)
地形:
  • 高原/平原
  • 山脊
  • 山坡
  • 山地斜坡
  • 麓坡
  • 谷底
垂直分布带:
  • 0-100 m a.s.l.
  • 101-500 m a.s.l.
  • 501-1,000 m a.s.l.
  • 1,001-1,500 m a.s.l.
  • 1,501-2,000 m a.s.l.
  • 2,001-2,500 m a.s.l.
  • 2,501-3,000 m a.s.l.
  • 3,001-4,000 m a.s.l.
  • > 4,000 m a.s.l.
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

平均土层深度:
  • 非常浅(0-20厘米)
  • 浅(21-50厘米)
  • 中等深度(51-80厘米)
  • 深(81-120厘米)
  • 非常深(> 120厘米)
土壤质地(表土):
  • 中粒(壤土、粉土)
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

地表水的可用性:

过量

5.6 应用该技术的土地使用者的特征

生产系统的市场定位:
  • 生计(自给)
相对财富水平:
  • 非常贫瘠
  • 贫瘠
个人或集体:
  • 团体/社区
机械化水平:
  • 手工作业
  • 畜力牵引
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

  • < 0.5 公顷
  • 0.5-1 公顷
  • 1-2 公顷
  • 2-5公顷
  • 5-15公顷
  • 15-50公顷
  • 50-100公顷
  • 100-500公顷
  • 500-1,000公顷
  • 1,000-10,000公顷
  • > 10,000公顷
这被认为是小规模、中规模还是大规模的(参照当地实际情况)?:
  • 小规模的

5.8 土地所有权、土地使用权和水使用权

土地所有权:
土地使用权:
  • 个人

6. 影响和结论性说明

6.1 该技术的现场影响

社会经济效应

生产

作物生产

降低
增加

饲料生产

降低
增加
注释/具体说明:

Residues are fed to livestock

生产区域

降低
增加
注释/具体说明:

Without irrigation, agricultural production is not possible

收入和成本

农业收入

降低
增加

社会文化影响

食品安全/自给自足

减少
改良

社区机构

削弱
加强

生态影响

水循环/径流

水的回收/收集

减少
改良
土壤

土壤水分

降低
增加

养分循环/补给

降低
增加

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

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
局地风暴
气候灾害
该技术是如何应对的?
干旱
水文灾害
该技术是如何应对的?
比较和缓的(河道)洪水
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. 参考和链接

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

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