Since I have seen the water demand forecasting model based on economic activities/parameters by Input-Output Table (I-O Table), I look forward the R package to solve the I-O Table. Then I see the R|E|A|L (Regional Economic Analysis Laboratory) developed by THE UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN.
This software is freeware based on python as interface building and R as main matrix calculation. When you downloaded and installed in your PC, there will providing you the source code to matrix calculation in economic analysis such as R.A.S method. So I think it is useful for anyone who interesting in R and water-economic analysis.