Application of Groundwater Vistas in Modelling Groundwater Flow in Keiyo Highlands
DOI:
https://doi.org/10.2200/aerj.v2i2.133Keywords:
Shallow Wells, Steady State, Transient and PredictionAbstract
Mathematical models which are based on mathematical equations are normally used to describe groundwater flow in a given area. In Keiyo Highlands, 37% of residents use shallow water wells as the sole source of water. Some of these wells run dry during the dry season and therefore a study was conducted with the aim to construct a 2D groundwater of the unconfined aquifer in the area to understand the groundwater behaviour in the study area. Conceptual model showing the positions of rivers, wells and recharge was done. Other data included hydraulic conductivity, porosity for the numerical model which was developed using MODFLOW code. The Graphical User Interface used was Groundwater Vistas. A grid of 2160 cells of sizes 140m by 80m was constructed in Groundwater Vistas. The model was calibrated manually by trial and error method for a steady state conditions during the rainy season in the study area. The transient state showed how the depths of water reduced in the wells. The amount of recharge was 0.00045 m/day, porosity 50%. The hydraulic conductivity varies from 0.05 m/day to 0.09 m/day. The model predicted the heads well under both steady state and transient state conditions. The percent errors were 0.005% and -0.4% for both steady and transient state, respectively.
References
Alley, W. M., Reilly, T. E., & Franke, O. L. (1999). Sustainability of Ground-Water Resources, U.S. Geological Survey Circular 1186, 79.
Anderson, P. M., Woessner, W. W., & Hunt, J. R. (2015). Simulation of flow and advective transport. Applied Groundwater Modelling. 5. London: Elsevier.
Bencala, K. E.,Gooseff, M. N. & Kimball, B. A. (2011). Rethinking hyporheic flow and transient storage to advance understanding of stream-catchment connections. Water Resources Research, 47 (3).
Clement, T. P., (2011). Complexities in hindcasting models-when should we say enough is enough? Groundwater 49 (5), 620-629.
Fetter, C. W. (2001). ). Properties of aquifers. Applied Hydrogeology. 66-112 New Jersey: Prentice-Hall Incorporation
Karuku, G. N., Gachene C. K. K., Karanja N., Cornelis W., Verplancke H., & Kironchi, G. (2012). Soil hydraulic properties of a Nitisols in Kabete Kenya. Tropical and Subtropical Agroecosytems. (15) 595-609.
Kempen, B. (2007). Soil and terrain database for Kenya (Version 2.0)(KENSOTER). Wageningen: ISRIC.
Kenya National Bureau of Statics (2010). The 2009 Kenya Population and Housing Census. Volume II: Population and Household Distribution by Socio-economic Characteristics.
Kumar, C. P. (2015). Groundwater Assessment and Modelling. Kindle Edition. 1259.
Hunt, R. J., & Welter, D. E., (2010). Taking account of Unknown unknowns.. Groundwater. 48 (4), 477.
Qureshi, A. L., Sarki, A., Mirjat, M.S., Mahessar, A. A., & Kori, S. M. (2014).Determination of Saturated Hydraulic Conductivity of Different Soil Texture Materials. IOSR Journal of Agriculture and Veterinary Science. 56-62.
Rumbaugh, J. & Rumbaugh, O. (2015). Online User Manual: Groundwater Vistas:Environmental Simulations Incorporation, Reinholds, PA.
Wada, Y., Van Beek, L. P., Van Kempen, C. M., Reckman, J. W., Vasak, S. & Bierkens, M. F. (2010). Global depletion of groundwater resources. Geophysical Research Letters, 37 (20).
Water Resources Management Authority (2009). Integrated Water Resources Management and Efficiency Plan for Kenya. 23.
Winker, F. (2010). Groundwater model for Swakop River Basin, Namibia. Unpublished Diploma Thesis, Institute of Hydrology, Freiburg.
