A peak at the future: Simulating Coonoor’s water situation

Using computer simulation, Keystone Foundation demonstrates the impact of domestic use, tourism, plantation and farming on the water situation in Coonoor in the Nilgiris.
Coonoor Land Use Map Coonoor Land Use Map

The Nilgiris have undergone an incredible amount of change in the last 10 years. Coonoor, an area well endowed with natural resources, is the second largest tourist destination here. However, over the last year (2012-13), the town has been reeling under a water crisis [1]. The drying up of local water sources has meant that water supply has been erratic [3] and people have had to depend on purchasing water through tankers and tapping springs and open wells.

In this context, Keystone Foundation was interested to better understand the various factors affecting the availability and quality of water so it could later advocate for mainstreaming conservation action in district public policy. While the focus was on Coonoor, a larger area was taken up for the study.

Computers to the rescue

It was important to be able to show various examples of what could occur if a change in approach was not undergone. In order to present these alternative “futures”, a computer simulation exercise was undertaken, which is basically is a computer program that is designed to simulate what might or what did happen in a situation [4].

We wanted to look at two specific questions: 

  1. Level of water deficit in the region: To understand whether or not there is sufficient water available in the region to meet the needs of various sectors.
  2. Level of nitrates (an indicator of chemical pollution) in the stream: To look at the level of chemical and biological pollution in the streams.

Simulation inputs

Secondary data collected from: 

  • Sources such as scientific literature, research institutions in the area, government departments etc.
  • Institutions such as Coonoor Municipality, Center for Soil Water Conservation Research and Training Institute (CSWCRTI), Ooty, private tea estates
  • Keystone over the years for different projects
  • Datasets were cleaned up as part of the Data Capacity Initiative with India Water Portal.

Primary data: 

  • Water quality through basic lab kits that could measure nitrate levels up to 50 ppm
  • Household water use patterns through survey
  • Biological pollution through a test to check if sample was polluted or not

Land use: 

  • Satellite imagery used to derive a land use layer
  • Ground observations carried out to verify samples of the layer
  • Region was subdivided into smaller sub-regions, based on catchment area of smaller streams

 Technical details 

  • Code was written in Matlab and ported to Freemat
  • Simulation was run for a 20 year period with calculations at daily intervals
  • Document with detailed description of assumptions is attached in the annexure 

Baseline scenario 

Assumptions 

  • Population grows at 1.5% per year
  • Tourist population at 5% per year 

Projected outcome 

  • Water deficit in seven out of the 20 years, starting nine years from now 
  • Water deficit in sub-regions where more area is under farming 
  • Nitrates are more than four times the safe limit for drinking (40 ppm) 
  • Nitrate more than 300 ppm in Coonoor town 

 Future trends 

  • If current situation continues, there will be a major water crisis in the coming years both in terms of quantity and quality.
  • If we add uncertainty due to climate change as well as the issues related to distribution of water into the mix, then the crisis is much more immediate. Last year's experience in Coonoor town is an example of this type of crisis.

Additional scenarios 

Case I simulation 

  • Increase of urbanisation trend in the Nilgiris and 2% of land under tea is converted into builtup area 

Projected outcomes 

  • Significant reduction in base flow
  • Increase in flood peaks
  • Reduction in aquifer storage
  • Water deficit in sub-regions where more area is under farming in more number of years 

Case II simulation 

  • Adoption of organic agriculture by reducing agricultural chemical use by 25%

 Projected outcome 

  • Water deficit scenario unchanged
  • Overall nitrate level remains same
  • Peaks do reduce somewhat 

Case III simulation 

Improvement of solid waste management and a 50% reduction in waste from local and tourist populations. 

Projected outcome :

  • Significant reduction in nitrate levels in the streams 

 Case IV simulation 

  • Replacement of 25% of exotics with native species and grasslands

 Projected outcome: 

  • An increase in baseflows
  • Decrease in water deficit 

These simulations show the importance of land use pattern in the quantity and quality of water available in the region. It also predicts a high level of nitrates in the stream water, which indicates that the problem of waste management in the region is being pushed downstream to people who depend on the stream water for agriculture, drinking etc.

Locally, the villages mainly depend on springs for water supply and these are not contaminated as yet. The pollution is being sent downstream out of the Nilgiris where the communities living next to the river have to deal with the consequences.

Dissemination and follow up 

Thus, it was possible to demonstrate the cumulative impact of various sectors on the water resource situation in the region and generate a consensus on the need to act on the same. It was able to show what happens to the water due to the combined effects of different ‘sectors’ – domestic, tourism, plantation, sanitation, agriculture etc. which normally operate independent of each other. 

These were presented to a group of stakeholders in the region. Laypersons too were able to quickly grasp the significant messages regarding land use and waste management. This novel information, cannot be easily communicated otherwise.

Keystone plans to focus on the water supply and demand situation of Coonoor and modify the simulation accordingly. A Payment for Ecosystem Services (PES) approach will be tried out to come up with a possible solution to the water crisis. This is the focus of a new project from 2013-15.

The simulation of nitrate levels highlights the need for good waste management and sanitation practices. Keystone is also planning to work on a village scale on waste management and sanitation issues with youth from the villages by partnering with other agencies involved in this work.

References:

Read the complete article,'A peak at the future: Simulating Coonoor’s water situation', which is the fifth in the series of posts from the Data Capacity Project collaboration with Keystone Foundation.

 
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