Pilot Study on Optimal Design and Management of Small-Scale Irrigation Scheme with Rainwater Harvesting -Constructing a Pilot Scheme in Ghana/West Africa-

雨水收集小型灌溉方案优化设计和管理试点研究 - 在加纳/西非建设试点方案 -

基本信息

批准号：
13306018
负责人：
KAWACHI Toshihiko
金额：
$ 39.44万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2004
项目状态：
已结题

项目摘要

Water as a limiting factor in agricultural production in semi-arid Savannah could be developed on a small scale by constructing self-reliant irrigation tanks (micro-dams) that directly harvest and store rainwater from prepared catchment, having less impact on the environment. The tank could also be a core of village-level rural community to encourage agricultural activities as well as farmers' communication. The objective of the study is to build a micro-dam at a pilot site in Ghana, discuss optimal planning, design and management of the rainwater harvesting system for developing a decentralized small-scale irrigation scheme and experimentally evaluate the efficacy of the irrigation tank for agricultural production. Climatic properties of the site were analyzed using meteorological data automatically recorded by a weather robot installed at the site. For analyzing run-off from the catchment area with the aid of GIS (Geological Information System), an innovative 2-D run-off model was de … More veloped using the finite-volume method. Design practice for constructing the scheme consisting of micro-dam, water conveyance channel and farm land was made meticulously considering the results from these analyses and the in-site topographical and geotechnical surveys. It was found that a micro-dam of high technical level and long life span (100-year flood discharge was considered for spillway design), which cannot be found currently in developing counties such as Ghana, could relatively inexpensively be built if design requirements and construction quality are relaxed to their marginal limits and the process of micro-dam construction would appropriately be supervised. Considering that a gravity-fed water-saving supplemental irrigation, an adaptive water supply subject to soil moisture content in the farm land, is the best, a sophisticated numerical model was developed that can evaluate its effectiveness in terms of water management and water use efficiency and quantify the efficacy of the irrigation tank for agricultural production. Currently field observations for maize growing in the pilot farm land are continued. Through comprehensively analyzing the results obtained, the efficacy of the irrigation tank for agricultural production will be evaluated. Less

水作为半干旱萨凡纳农业生产的限制因素，可以通过建造自力更生的灌溉水库（微型水坝）进行小规模开发，直接从蓄水池收集和储存雨水，对环境影响较小。也可以成为村级农村社区的核心，以鼓励农业活动以及农民交流。该研究的目的是在加纳的一个试点地点建造一座微型水坝，讨论该水坝的最佳规划、设计和管理。雨水收集系统用于发展分散式小型灌溉方案，并使用安装在现场的气象机器人自动记录的气象数据对灌溉水箱对农业生产的功效进行了实验评估。借助GIS（地质信息系统），采用有限体积法开发了创新的二维径流模型，用于构建由微型水坝、输水渠道和农田组成的方案。经过仔细考虑这些分析结果以及现场地形和岩土工程，发现微型坝技术水平高、寿命长（溢洪道设计考虑了100年泄洪），不能满足要求。目前在加纳等县发现，如果设计要求和施工质量放宽到边际限制，并且考虑到重力供水的节水补充开发，微型水坝的施工过程将得到适当的监督，那么其建造成本相对较低。灌溉，适应性水灌溉水箱的供水量取决于农田土壤湿度，是最佳的，因此开发了一个复杂的数值模型，可以评估其在水管理和用水效率方面的有效性，并量化灌溉水箱对农业生产的功效。继续对试点农田的玉米种植进行综合分析，评估灌溉水箱对农业生产的效果。