|Simulating the Risk of Sanitation to Drinking Water from Groundwater|
|This simple model allows for looking at inter-relationship between various risk factors that contribute to|
|contamination from on-site sanitation.|
|The user can provide estimated values of controlling parameters such as depth to water table, depth of pit, distance to well|
|The output is in the form of the time taken to travel from sanitation to well. Interpretation of this time as risk is provided.|
In this example, parameters have been set to look at a 12 month cycle in which the depth to water table and groundwater gradient are varied.
|The situation is typical to a monsoonal type rainfall and a hard rock aquifer with very short distance to drinking water well.|
|One can view the individual time taken to reach the water table, to reach the well and the total time taken.|
|The user has options of 3 interventions 1. Using drier latrines, 2. Raising the latrine pit and 3. Having the drinking water well farther.|
|The travel time to the well can be seen by making variations on these interventions and see which of them has greater impact.|
The model is a simple one in which homogenous aquifer conditions are taken. Also, the unsaturated hydraulic conductivity is estimated
by assuming it as a function of hydraulic loading from the sanitation structure. A 100mm/d loading is considered to lead to saturated conditions.
From 500 mm/d to 100 mm/d the hysteresis factors is varied from 0.1 to 1 linearly. It is varied from 0 to 0.1 linearly with loading of 0 to 50 mm/d
The first version has been prepared on June 8, 2011 by Sunderrajan Krishnan from INREM Foundation as inputs into a study support by the
|Bill and Melinda Gates Foundation look at sanitation-groundwater contamination linkages.|