ANALYSIS OF LAKE NAKURU SURFACE WATER AREA VARIATIONS USING GEOSPATIAL TECHNOLOGIES

Abstract

The research intended to analyse the trend of Lake Nakuru water surface variation between 1984 and 2013 with the aim of identifying probable causes. Landsat images including Tropical Rainfall measuring mission (TRMM) were used to determine the lake surface level variations within the period. Supervised classification was used in generating Land Use/Land Cover changes between 1984 and 2013. The results show that changes in the lake level variations may not entirely be attributed the amount of rainfall during the period under consideration. There is consistent trend in reduction of forest cover and increase of farm or agricultural land. Forest cover increased from 30.99% to 33.73% between 1984 and 2013 while agricultural land increased from 59.12% to 68.61% during the same period. The lake water surface area had a steady increase of between 30.46 km2 in November 2009 to 57.55 km2 in January 2014 an increase of 27.09 km2 which is 88.94%. In 2006 the water surface area was 35.38 km2, it also witnessed the highest amount of rainfall but the lake water surface area did not reflect that. The rainfall data from TRMM 2009 - 2010 the difference was 36.3%, 2010- 2011 reduced to 29.8%, 2011 – 2012 increased to 32.4% and 2012 – 2013 finally increased to 36.6%. The rain gauge rainfall amounts 2009 - 2010 had a difference of 24.4%, 2010- 2011 reduced to 19.3%, 2011 – 2012 reduced further to 13.1% then 2012 – 2013 increased to 49%. The lake surface area 2009 - 2010 difference of 44.6%, 2010- 2011 increased to 46.7%, 2011 – 2012 increased further to 70.1% and 2012 – 2013 finally increased to 86.6%. This showed when rainfall amounts were falling the lake surface areas were still increasing indicating no direct correlation between the rain and the lake surface area.