## 2 Materials and Methods
### Feasibility Study  
The core methodology used in the feasibility investigation was the toolbox on \"Solar Powered Irrigation Systems (SPIS)\" [50]. The SPIS toolbox was developed primarily for small-scale irrigation. Where necessary and possible, the toolbox was adapted and populated with data to fit the multi-purposes of MUS schemes. The toolbox consists of a handbook structured in modules and a number of tools in Excel and Word. The following modules were used in this study: Impact Assessment Tool, Water Requirements, Market Assessment Tool, Farm Analysis Tool, Payback Tool, Finance Deployment Tool and Pump Sizing Tool. The Impact Assessment Tool consists of a questionnaire where scores and weights are assigned to environmental and socio-economic impacts. The questionnaire was compiled with information based on long-term research and experience gained in the study area, as well as based on feedback from stakeholder engagements during field visits. The Water Requirements spreadsheet is used to calculate crop or livestock water requirements. It is therefore one of the key tools for the design of solar-powered pumping systems. The tool is a spreadsheet that makes use of the FAO methodology [57] based on the FAO 56 Bulletin to calculate crop water requirements [58; 59]. For the purpose of estimating agricultural water requirements, a hypothetical cropping pattern was chosen with three tomato crops grown on 0.5 ha and planted on 1 December, 1 May and 1 October of the year. Tomato is a popular vegetable in the area and its water consumption is generally higher than other common vegetables (worst-case scenario of crop water requirements). Crop growing period was from 135 to 158 days according to FAO 56 guidelines [58]. Drip irrigation with 90% efficiency was selected as well as normal spacing of plants. Weather data from 2012 to 2020 collected with a weather station in Giyani (Agricultural Research Council; Lat: \(-\)23.32403; Long: 30.68730; Alt: 463 m) were used as inputs. Monthly average temperatures were entered in the spreadsheet to calculate reference evapotranspiration ETo and average monthly rainfall was added to calculate effective rainfall [58]. In addition, livestock water requirements were calculated based on the recommendations of [60]. For livestock water requirements, it was hypothesized that the farms (Table 1) breed 5 adult dry cattle. For the study sites supplying water for domestic use (Table 1), water requirements were estimated by multiplying the population of the village by the minimum average basic consumption of 25 L per person per day, according to South African norms. The Market Assessment Tool defines the business conditions and their relevance. Appropriate parameters were chosen from drop-down lists and by making use of links to web sites provided within the tool to extract general information from global reports and databases. The relevance was selected based on given categories (inconsequential, slightly important, important, very important and critical). The input weightings were kept as default. The Farm Analysis Tool is used to perform a financial analysis of a farming enterprise to assess agricultural productivity and profitability. It consists of spreadsheets to calculate fixed and variable costs and farm profit/loss. Information on realistic income and expenses was collected directly from small-holder farmers and agricultural extension officers during the stakeholder engagement. This was used to calculate a typical profit margin for a small-holder farm. The Payback Tool is used to compare the financial feasibility of three different pumping options: solar-powered, grid-powered and diesel-powered. Input data were populated with realistic capital and maintenance costs of these systems. The life spans of the system components were estimated according to general knowledge and based on specifications of manufacturers.