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沙坝

548 bytes added, 02:59, 31 August 2015
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- 河岸植被再生 <br>
- 沙坝通常对河水下游的流量影响较小(少于10%的径流) <br>
- Better water quality than surface water dams: protects the water against evaporation, animal contamination and insect & bacteria breeding. 相较于普通的地面水坝,沙坝能使水质更好:能防止水分蒸发,动物污染及昆虫和细菌繁殖 <br>- Sand deposits can be collected and sold for extra income. 沉积沙可以收集起来出售,获取额外收入 <br>- Long lifespan if maintained correctly. 若适当维护沙坝,则使用寿命长
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- Site-specific technology – not suitable everywhere. 这一技术适用于特定场地——并非适用于所有地点 <br>- External expert knowledge needed 需要外界提供专业知识<br>- Labour intensive construction 劳动密集型的建造<br>- Although cost per volume is cheap, the actual structure that needs to be made is expensive. 虽然每容积的造价不高,但实际需要的建造物价格昂贵 <br>- If dam is built in stages, it can be difficult for the community to show up next season for the next stage of work.如果建坝分阶段进行,社区难以确定下一季工作的阶段<br>- Must rebuild if the river changes course 如果河道更改,则必须重建<br>- The possible dam construction sites may be too far from the water users 能够建坝的地点可能会离需要用水的人太远<br>- In Kenya, experience shows that up to 80% of dams might not be functioning as they should due to poor design. 在肯尼亚,根据经验,因设计不当,多达80%的水坝可能无法运作<br>
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===Resilience to changes in the environment顺应环境变化=======Drought干旱===='''Effects of drought干旱效应''': Can dry up; Water yields low. :会干涸;出水量低。 <br>'''Underlying causes of effects潜在的因果关系''': Less recharge of aquifer due to less rainfall. Increasing population & water demand; Size of aquifers – e.g. limited sand volume; Too much silt accumulates behind dam; Wells not sunk deep enough into water table; Incorrect siting creates leaking dams.:减少的降雨量会降低砂石含水层的补充。上升的人口和用水需求;砂石含水层的大小,如,有限的沙量;坝后积聚了太多淤泥;井不够深,未达地下水位;选址不当,引发水坝泄漏。<br>'''To increase resiliency of WASH system提高水、环境卫生与个人卫生系统的适应力''': Competent siting & construction; Build sand dam in stages to reduce silt; Soil & water conservation techniques in upper part of catchment; Dig abstraction wells/pipes deeper.:选址和建造符合要求;分阶段建坝以减少淤泥;土地和水源保护流域。
More information on managing drought: [[Resilient WASH systems in drought-prone areas]].
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