**Author details**

ground water flows from the large area of the city toward the lake shore. Thus, the ground water system feeds the lake which will in turn accelerate the lake level rise. For those months in which the pumping test of the wells conducted (i.e., March, April, and May) large amount of infiltrated water from the discharge spots join the ground water reservoir as this is the time immediately after the rainy season stops in the area. Combining these graphical results and the one for the surface water flow direction (**Figure 3A–J**), groundwater flow direction follows similar tendency of the surface water movement, that is, it follows the surface profile. This also implies the fact that the highlands are recharge areas and the lowland areas as nice spots for

Using the wire frame and the grid map of the well depth on Surfer 8 Software, one can interpolate the required depth to be drilled at specific GPS location in the study area. This is an important guide for borehole drillers and clients to estimate the depth of the water striking formation at that specific site. To do so, the Surfer 8

The gridding method in Surfer 8 Software uses weighted average interpolation algorithms. This means that with all other factors being equal, the closer a point is to a grid node, the more weight it carries in determining the Z value at that grid node. The difference between gridding methods is how the weighting factors are computed and applied to data points during grid node interpolation. The coefficient of determination for this analysis is found to be R<sup>2</sup> = 0.87, which indicates the strong

To increase the likelihood that these data are honored, one can increase the number of grid lines in the X and Y direction. This increases the chance that grid nodes coincide with data points, thereby increasing the chance that the data values

parameters determined by this and other studies shall be combined to get more detailed information. Certainly, the more the depth drilled, the better will be

The geological formation at the depth to be drilled and the other

discharging.

**Figure 4.**

*Well depth wireframe map.*

*Resources of Water*

acceptability of the guide.

the safe yield.

**50**

are applied directly to the grid file.

**2.3 Guide to drilling depth in Hawassa City**

Software can be used to display the map as shown in **Figure 4**.

Shemsu Gulta<sup>1</sup> and Brook Abate<sup>2</sup> \*

1 School of Biosystems and Environmental Engineering, Hawassa University, Hawassa, Ethiopia

2 College of Architecture and Civil Engineering, Addis Ababa Science and Technology University, Addis Ababa, Ethiopia

\*Address all correspondence to: brooka12@yahoo.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
