Technology And Demonstration For Slope Rainwater Harvesting In Karst Mountainous Area

The southwest region of Karst, which center is Guizhou plateau,is ecologically fragile areas. By the interference of humanbehaviors, the local fragile ecosystems formed a unique environmentof stony desert. Due to the unique structure of karst landforms,the area appears some features that high mountains and low water,heavy rains but can not storage in surface, many stones but thinsoil layer and drought very commonly. These phenomena contributeto difficult catchment the surface water and exploit deepgroundwater, and this area become drought although it has a highrainfall precipitation. Drought is a main disaster in this regionand restricts the sustainable development of the region. Soefficient techniques of rainwater harvesting is needed to alleviatethe drought situation.This study relies on a major issue of national “TwelfthFive-Year Plan” Technology Support Program. The study selectstwo typical karst landforms and karst mountainous highland plateaugorge-Bijie Salaxi and Zhenfeng-Guanling Huajiang as the area toreveal relations between different karst unit slope to achieveoptimal harvesting project assembled and build a suitable modelfor the purpose of rainwater harvesting slope. Based on understandthe slope rainwater harvesting techniques and planning principles through literature, utilization of water resources through throughfield research and formulate a proper system of rainwatercollection and intended for crop irrigation, combine rockybiological control measures small watershed, design and layoutthe slope rainwater harvesting project and choose a typicalirrigation district as demonstration area. The main conclusionsare as follows:(1)In order to reduce cost and simple and practical for theprinciple, conclude the process of slope rainwater harvestingtechnology which is suitable for Sarah Creek demonstration areaas "natural grass slope-intercepting ditch-Bus Drainage-settlingbasin-open round semi-buried pool-fixed input water supplynetwork-small mobile micro sprinkler irrigation machines "; andthe process which is suitable for huajiang demonstration area as"asbestos artificial slope-open half buried rectangularpool-semi-fixed input water supply network-small tube flowirrigation". Assembled harvesting technology above is only forexisting single technology integration, it’s lack of optimizationand innovation, so the research of new materials of catchment,new storage equipment and new irrigation methods, fit for karstmountainous terrain and sociol-economic conditions,should bestrengthened. For supporting the assembly on the basis of achieving a breakthrough on individual rainwater harvesting technology.(2)Using the method of the modified Penman equation, the authorfind that average daily water consumption of fruit and nut grassand pepper forest in growth period. Analyze the Characterize ofmeteorological droughts, soil physical properties and through this,develop a crop irrigation system. The average daily waterconsumption in growth period is2.61mm in Salaxi area, design annualamount of irrigation is238.2m3/hm2, the cycle is7days andirrigation times in in growth period is3times. The average dailywater consumption in growth period is1.77mm in Huajiang area,design annual amount of irrigation is378.42m3/hm2, the cycle is17days and irrigation times in in growth period is3times. UsingPenman formula for calculating corp water consumption, it is moredifficult to evaluation the crop coefficient, it is need tostrengthen the field data measured. Also should strengthen thecrop irrigation system and water system under different rainfallreliability research in order to the irrigation system developmore rationalization and improve the utilization of waterresources.(3)Take specific parameters of all kinds of factors intoaccount. and then design all the system size. The demonstrationarea of Salaxi has200m3reservoir, design the radius with10.6m, the design depth is2.5m, and the design annual water consumptionis576m3. The corresponding natural rain field and the fruit grassirrigation area were0.28hm2and0.81hm2. The confluence channelsection size is30cm×20cm×15cm, the size of supporting thedesalting basin is1.8m×0.9m×0.8m. The rectangular reservoirof Huajiang demonstration area is100m3,and the design size is8.6m×4.6m×2.8m, designed annual water consumption with272m3.The rain field of asbestos tile and Zanthoxylum bungeanum forestirrigation area were corresponding to330m2and0.24hm2. The abovetechnical parameters and engineering designed to formulate therainwater harvesting technology specification and standard hascertain reference value, but it’s promotion and application oftechnical has still exists some limitations. So it should combinedwith different geomorphic units to strengthen the design and studyfor the technical specifications of the rain, in order to furtherimprove the rainwater harvesting norms and standards.(4) The assemble the slope after collecting rain engineeringis applied to the fruit grass irrigation, with the rain formingtechnology and crop high efficient planting technology of slope,and alpine ecological animal husbandry technology combination,constitute a natural slope salaxi demonstration area rainwatercomprehensive utilization mode. The assembly after the slope rainwater harvesting engineering application in Zanthoxylumbungeanum forest irrigation, and the collection of rainwater forirrigation with small tubes form try to district and herbs andpitaya and irrigation, which take artificial slope RiverDemonstration Zone set supporting economic crop cultivation modeof rain water. Rainwater harvesting and utilization mode ofconstruction is only based on the existing control technologydemonstration area of rocky, should fully understand the mode ofconnotation and extension and technical support system, continuousintegration, improve the rain utilization mode and innovation,while strengthening the late management and maintenance mode.