Assignment of Land Use to ...

Assignment of Land Use to Grids

The area and percentage of each land use in each grid is assigned with specific Landuse.shp.

 

Pipe Density for Foul, Potable and TSE Systems

The progression in pipe density is calculated from the population projection. The first step involved manually identifying areas that are at, or close to, Build-Out conditions. The existing density of pipes and pipe length per grid is calculated from GIS layers of current data for foul, clean water and TSE models if available. If found in some grids that, road area is significant and is up to 10-15% of the grid area. Hence the pipe density for roads is an important component of the total pipe density in a grid and is also calculated from the existing pipe density data.

The typical pipe densities are calculated for each land use by averaging the existing pipe density from grids with high development factor (build-out) and coverage of the land use.

 

Samples data extracted from a project in Qatar and are used for arriving at these rates are as given below:

• Single Family – Grids with single family land use > 50% and Development factor > 0.7
• Multi Family - Grids with Multifamily land use > 35% and Development factor > 0.35
• Mixed Land use - Grids with mixed land use > 35% and Development factor > 0.35 and pipe density greater than 10
• Roads – Average rates for the three land uses were applied to road

Increasing Trend in Population

In case of some grids have no existing pipe density data and as a result the projected pipe density jumped unrealistically in value. In these grids the development rates are factored to distribute this sudden increase in pipe density for each decade as follows (using the 52 decade as an example):

((Development Factor in 52- Development Factor in 62)/ (Development Factor in 62 - Development Factor in 12))*[Pipe Density in 2062]

Some grids can be found already at maximum capacity for pipes in certain year and hence have higher pipe density than the projected values. In these cases the smaller projected values are replaced by the existing values this particular year.

 

Decreasing trend in Population

It can be found that some grids have no existing pipes and a decreasing development trend. In these cases the pipe density is retained as 0. At the same time some grids have existing pipes and a decreasing trend in population due to a change in land use for mega projects, industrial development etc. Here the existing pipe density is retained and maintained constant for all the years.