IOSR Journal of Engineering (IOSRJEN) www.iosrjen.org ISSN (e): 2250-3021, ISSN (p): 2278-8719 Vol. 09, Issue 1 (January. 2019), ||V (I) || PP 01-14 International organization of Scientific Research 1 | Page Protocol for Evaluating Sand Dam Water Quality in Semi-Arid Areas: A Case Study of Makueni County D. Ndunge 1 , D.O. Mbuge 2 and C.T. Omuto 3 1 Dept. of Environmental and Biosystems Engineering, University of Nairobi, Nairobi, Kenya 2 Dept. of Environmental and Biosystems Engineering, University of Nairobi, Nairobi, Kenya 3 Dept. of Environmental and Biosystems Engineering, University of Nairobi, Nairobi, Kenya Corresponding Author: D. Ndunge Abstract: Sand dams have been recommended in many places as a feasible technology for the ASAL areas due to their ability to store water with minimal evaporation, recharge underground water and raise water table, among others. In Kenya, adoption of sand dam technology has been steadily increasing. Water from the sand dams is used for drinking, domestic uses, livestock watering, and for irrigation. Water quality is paramount for drinking water. However, much emphasis is being done on the sand dam technical aspects namely hydrologic measurement and analysis, and determination of the quantity of water that will be harvested with less or no concern on the water quality and how the water quality can be affected. The focus of this study therefore was to determine water quality parameters for evaluating potability of water from sand dams, and development of a protocol for evaluating potability of water from sand dams in semi-arid areas. Water samples were collected from the sampled existing sand dams’ water abstraction points within Makueni County and analyzed for heavy metals, microbiological, physical and chemical quality. Laboratory test results showed that all tested sand dams within the study area have unsafe water for drinking in its raw form. A protocol for determining the potability of sand dams was developed. The protocol provides information on how to assess the quality of raw water from sand dams; to determine the need and extent of the water treatment to make it safe for drinking; and to examine the finished water to ascertain that it conforms to the recommended drinking water standards. Keywords: Sand dams, Water Quality, Protocol, Potability, Minimum Data Set, Makueni County. --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 18-12-2018 Date of acceptance: 03-01-2019 --------------------------------------------------------------------------------------------------------------------------------------- I. INTRODUCTION ASALs are characterized by extremely limited spatially distributed precipitation and high evaporation losses with poorly available ground water supply. Sand storage dam technique (sub surface storage dam) is used to reduce the evaporation effect [1]. Sand dam is typical embankment or wall built across an ephemeral (seasonal) stream. During the rainy season, the wall harvest sand and 20-40% of its total volume is water as shown in Figure 1. The water is then abstracted using various methods depending on the intended use by the communities. There are three common methods of water abstraction from sand dams including traditional scoop holes, an infiltration gallery either leading a tank behind the dam and/or piped through the dam leading to a tap and an infiltration gallery leading to a sealed shallow well in the valley side – topped with a hand pump. Figure 1: Typical illustration of sand dams There are three types of sand dams as outlined by [2]. These include stone-masonry dam which is built of concrete blocks or stones, reinforced concrete dam consisting of a thin wall made of reinforced concrete and earth dam which consists of impermeable soil material (mostly clay or clayey soils, or black soils).