## 3 Results  
Average precipitation across the pump sites was 171 mm in 2017, compared to 326 mm in 2018. As seen in Figure 2, there was considerable variation within each county between the two years. Isiolo received the least precipitation in 2017 at 111 mm, while Marsabit received the most precipitation at 298 mm. In 2018, Isiolo received the most precipitation at 523 mm, while Turkana received the least precipitation at 203 mm. Water systems were used on average 7.1 h in 2017 versus 5.4 h in 2018. Average use also varied considerably by county, with all counties except Turkana averaging greater use in 2017 than in 2018. Garissa had the lowest average use both years (3.6 and 3.3 h, respectively), while Wajir had the greatest use in 2017 (9.5 h) and Turkana had the greatest use in 2018 (8.0 h). Based on estimated flow rates from individual sites, a daily average of 142 m\({}^{3}\) of water was extracted from each site in 2017, compared to 98 m\({}^{3}\) in 2018, representing a 31% decrease in average water extraction. In the null model with no covariates and intercepts allowed to vary across individual pump sites (i.e., \(Hours_{it}=\beta_{00}+U_{0i}+\varepsilon_{it}\)), there was considerable variation both within and between sites. The intraclass correlation coefficient, which provides a measure of the amount of variance attributable to differences between sites, was 45.3%. Variability across time within sites (\(\sigma^{2}=5.15\)) was slightly greater than variability between sites (\(\tau^{2}=4.26\)), where \(\sigma^{2}\) and \(\tau^{2}\) represent the standard deviations of site use within and between borehole sites. Figure 2: Average daily water system use for each county by year (line graph with left axis); annual precipitation (bar chart with right axis). Use data was collected from installed sensors, and precipitation data was collected from CHIRPS data. As seen in Figure 3, water system use was strongly tied to precipitation, although the influence of precipitation on water system use varied considerably by county. In counties with greater variability in use such as Marsabit and Garissa, there was significant ramping behavior whereby groundwater demand would increase significantly during the dry season and then drop precipitously after rainfall events. In counties with more consistent water system use such as Turkana and Isiolo, there were more systems that were run for predictable intervals (e.g., 12- or 24-h intervals). As a result, water system use in these counties was more influenced by system functionality than precipitation events. Figure 3: Left axis: average hours of daily water system use for each county from 2017 through 2018. The red line indicates average daily use across all boreholes for each county, whereas the blue and pink dots show the individual observations for strategic and non-strategic boreholes, respectively. Right axis: the blue line describes the average daily precipitation across all pump sites for each county. The dark grey region demarcates the primary rainy season (March through May) and the light grey region demarcates the secondary rainy season (September through November). Use data was collected from installed sensors, and precipitation data was collected from CHIRPS data. As seen in Table 2, there were a variety of site-level characteristics that were strong predictors of water system use. As a fixed effect, the county each site was in was a significant predictor of use, with all counties except Isiolo recording greater average daily use than the reference county of Garissa. The type of power system was also a significant predictor of use, with hybrid and utility systems being used 1.1 and 3.5 h more than sites with generators (\(p=0.0043\) and \(p<0.001\)). Surprisingly, water systems powered by solar were used almost an hour less per day compared to sites with generators; however, the difference was not statistically significant (\(p=0.0597\)).