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沙坝
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* 时间安排很重要：建坝需在旱季进行，且勿太临近雨季，以避免沟渠被水填满或坝体被冲走。
* 建坝方法由水坝类型和地质类型来决定。在梯级地形上建造沙坝能提升总储水量和效率，并将渗流损失降至最低。混凝土、砌石（最便宜、最简单）和砌砖建成的水坝虽然需要技术娴熟的工人来建造，但会更坚固，使用寿命也更长。
* Usually sand dams are built onto a rock layer, but where there is no rock and only clay, it can still work but as long as the foundation is keyed into the clay layer and where the wall does not protrude more than 0.5m above original sand level, otherwise there is a risk the structure overturns during a flood event.通常，沙坝要建在岩层上，但在没有岩石而只有黏土的情况下，只要地基能嵌进黏土层，且坝墙不超出原有沙层0.5米，沙坝仍能运行；否则在洪水期间，坝体有倾覆的危险。* Key into banks or construct wing walls to avoid erosion around edges of the sand dam. Where wing walls are built, a good technique is to start with the wing walls and work inwards to the centre, since community enthusiasm lags by the time wing walls are constructed (if not built first), yet they are essential to proper functioning. Length of the wing wall varies according to bank characteristic: loose riverbanks, 7 metres; hard soils, 5 metres; hard & impermeable soils or rocks, wing wall is not needed. Planting napier grass along upstream riverbanks controls erosion and fixes the course of the river in a flood.坝体需嵌入河堤，或建造翼墙来防止沙坝边缘侵蚀。建造翼墙的情况下，较好的方法是先从翼墙开始建造，然后向中心动工。如果不先建造翼墙，社群的建造热情会在翼墙竣工前就下降，而翼墙对沙坝的正常运作来说至关重要。翼墙的长度随河堤的特性而定：松散的河堤，7米；硬质的土壤，5米；不透水且硬质的土壤或岩石则不需要翼墙。在上游河堤种植象草可以控制侵蚀，并在洪水中修正河道。坝体需嵌入河堤，或建造翼墙来防止沙坝边缘侵蚀。建造翼墙的情况下，较好的方法是先从翼墙开始建造，然后向中心动工。如果不先建造翼墙，社群的建造热情会在翼墙竣工前就下降，而翼墙对沙坝的正常运作来说至关重要。翼墙的长度随河堤的特性而定：松散的河堤，7米；硬质的土壤，5米；硬质且不透水的土壤或岩石则不需要翼墙。在上游河堤种植象草可以控制侵蚀，并在洪水中修正河道。
* The height of wall built before each flood event should not exceed accumulation rate of coarse to medium sand during that flood event, otherwise ponding & silt deposition will occur, which can lower specific yield and higher capillarity, then lead to limited extraction rates in wells upstream and more water lost to evaporation. Dams at 1.3m depth showed that where finer material content (0.063 mm or less) is increased, specific yield is known to decrease remarkably. Accumulation rate and therefore height varies according to location and should be adjusted at each site after the first flood event demonstrates the rate of accumulation. Height per stage will probably be between 0.3 metre and 1 metre per stage according to experience from past projects. Some silt deposition will always occur as velocities decrease toward the end of the flood event; the idea is to limit its quantity in final sand volume.在每次洪水来临前建造的坝墙高度不能超过当季洪水里粗砂至中粒砂堆积速率，否则会出现积水成池和泥沙沉积，这将降低单位出水量且增加毛细管作用，而导致位于上游的井取水率有限且更多水分蒸发流失。观察1.3米深的水坝显示，当更精细的物质成分（小于等于0.063毫米）增高，单位出水量会显著降低。堆积速率及相应的坝墙高度根据具体位置而定，且需要在第一次洪水来临后得出堆积速率，从而对每一位置的坝墙高度进行调整。根据以往工程的经验来看，每一阶段的坝墙高度差不多在0.3米至1米之间。随着洪水消退，由于速率下降，总是会出现一些泥沙沉积；这一点用来限制最终沙量中的泥沙沉积。
* Avoid downstream erosion problems by making a protective slab (stilling basin) at the base of large stones set in concrete. Dimensions to be designed, but is not necessary where there is exposed rock bar downstream.通过在混凝土中的大石块底部建造防护板（消力池），防止下游的侵蚀问题。防护板尺寸需要设计，但不一定是下游有裸露石块的区域的大小。
