# Design Criteria for Planning the Agricultural Rainwater Harvesting Systems: A Review
## 2 Rainwater Harvesting Structures  
The techniques of water resource use are focused on, considering the use to which the resource is to be allocated and the area where it will be applied (urban or rural). Those focused on developing in rural areas are directed toward use of rainwater harvesting systems (RWHS), whose main function is to store water in the rainy season to be used in drought periods when the resource is not available. Similarly, they are also associated with the uses to which the water is to be destined, either for crops or for domestic supply on farms [44]. From the approach review made by each author on the use of water resources for domestic and agricultural purposes, five classifications or groups are made. Group 1 included macro basins such as dams [45], small dams [46], control dams [47], reservoirs [47], cisterns [45] and nala bunds [47]. Group 2 included micro-watersheds, contemplating jessour [47], tabias [47], excavation with a dike (pits contour) [48], contour ridges [49], contour strips (runoff strips) [47], Negarim [49], dykes [48], and terraces [48]. Group 3 was named aquifer recharge and consists of gully plugs, aquifer recharge, subsurface dams, and percolation tanks [50]. Group 4 was called micro and macro basins and includes authors who used combinations of structures involved in the first, second, and third groups. Finally, Group 5 included those authors in which the use of water was made with reserve tillage, from which it drew its name. In the latter group, a mechanical device is used that develops micro reservoirs for the \"in situ\" uptake of rainwater to increase the retention of moisture in the soil and additionally functions to reduce soil erosion; therefore, it is very common to use in loose soils, which are characteristic of semi-arid zones [51; 52]. Once the methodologies were divided into groups, the design parameters that each author used were set, as can be seen in Tables 1-5. A total of 22 design parameters were considered such as physiographic characteristics (slope, drainage network, runoff, and basin area) climatological characteristics (precipitation, relative humidity (RH), wind speed and direction, solar radiation (SR), and evaporation), soil (use, texture, coverage, depth), socioeconomics (no inhabitants, interview to stakeholders, cost, land tenure, dwelling characteristics) and distance to dwellings, crops, and streams. Alongside these parameters, the advantages and disadvantages of each of these groups were established for ease of analysis. Table 1 shows the design parameters considered by each author for the macro-basin systems. These parameters can be obtained directly in the ground or indirectly estimated with remote sensors to later form databases managed using geographic information systems (GIS). Similarly, GIS allows planning the river basins to establish potential sites that guarantee RWHS efficiency with dams and dikes, as well as their respective reservoirs. Other relevant aspects considered in the methodologies making up Group 1 are socioeconomic conditions and local characteristics from the study area, such as distance from the water collection site to the point of use, as well as technical feasibility for construction and long-term operation. Finally, the application of processes of analytical hierarchy allow giving weight to the different attributes involved in the project by giving a different importance to each one depending on the suitability of the RWHS. Although subjectivity is diminished, it continues to exist since the weights for the process of analytical hierarchy will depend on those involved in the project. These methodologies are generally limited to the application of RWHS solutions related to the construction of dams, dykes, and reservoirs. Likewise, in some cases, communities located in the area are not informed regarding the selection of suitable sites, nor are the sociopolitical aspects that may influence the realization and benefit of the project considered.