Browsing by Author "Kachroo, Raj"

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    Evaporation Modelling in Data Scarce Tropical Region of the Eastern Arc Mountain Catchments of Tanzania
    (College of Engineering and Technology, University of Dar es Salaam, 2011) Zemadim, Birhanu; Mtalo, Felix W.; Mkhandi, Simon; Kachroo, Raj; McCartney, Matthew
    This paper focuses on developing methods for both potential and actual evapotranspiration (ET) models for the data scarce conditions of the Eastern Arc Mountains catchment of Tanzania. For reliable estimation of the components of the hydrological cycle and plant water uptake, potential ET estimates are required, and for catchment water balance actual ET estimates are needed. These potential and actual ET estimates, however, depend on reliable and good quality data records. The study catchments in this work are characterised by general lack of reliable meteorological (MET) data, though good records of rainfall, flow and pan evaporation data do exist in a few places. In the study reported here the Penman-Monteith (P-M) estimates were found to be closer to the pan evaporation model in areas where reliable records of pan data exist. By comparison, estimates derived solely from temperature (i.e. the Standard Thornthwaite method), were a lot lower. Assuming the P-M estimates to be reliable, new temperature based regional equations were developed using data obtained from six climate stations. The study also presents simpler methods for estimating actual ET from catchments.
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    Modelling of Flood Flows in Rufiji River Basin, Tanzania
    (2002) Mkhandi, Simon H.; Kachroo, Raj; Mtalo, Felix W.
    A simulation procedure applied to select a suitable statistical procedure to model flood flows in Rufiji River basin in Tanzania is presented. In this paper, a flood frequency procedure refers to the combination of a probability distribution with a suitable method of parameter estimation. A predictive ability test based on bias between observed and predicted flows is used to select the suitable procedure. Based on the results of the simulation, the most suitable statistical frequency procedures for modelling flood flows for the homogeneous regions of Rufiji basin seem to be log-Pearson type 3/method of moments (LP3/MOM) and Pearson type 3/method of probability weighted moments (P3/PWM). The two procedures gave the lowest bias values for different return periods and sample sizes considered in the sUidy. The study is based on the data from 42 sites in the basin