Thomas Civil and Environmental Consultants (TCEC) staff are able to offer a comprehensive service in the area of water network water loss management, which includes the following:
Water Loss Assessment
An assessment of water loss occurring from a water supply network will enable the water supplier to gain an understanding of the scale of water loss occurring from the network. The assessment will highlight the data sources used for water loss analysis and give an indication as to the accuracy of the assessment based on the data available. The assessment can initiate actions to reduce obvious or significant water loss, and lead to an improvement in the data collection and monitoring required for the measurement of water loss.
Water Balance Review
Where a water balance has been completed for a network it is a good idea to have the integrity of the data reviewed including an assessment of the confidence limits for each input value. This exercise can lead to actions to address the main contributors to the uncertainty in the water loss calculation using the water balance, resulting in increased confidence in the results.
Water Loss Strategy
A water loss strategy should include an initial water loss assessment based either on minimum night flow monitoring or a water balance, a review of the speed and quality of network repairs, developing an effective active leakage control programme based on regular night flow monitoring and leak detection capability, pressure management to reduce the volume of water loss from leaks (where feasible), and a review of network renewal programmes. Where customers are unmetered a strategy to deal with the uncertainties arising from assessing consumption is very important. All water networks leak to a certain extent, and a water loss strategy should address what an appropriate and/or economic level of leakage is for the particular system, and how long it should take to achieve this level of leakage.
Leaks are always present in a water supply network and the challenge is to put in place monitoring systems to regularly check for leakage, and then to intervene with an effective active leak detection response when appropriate. This monitoring can be more effective if the network is broken down into smaller areas by sectorizing the network - the setting up of District Metered Areas. Also, water losses can be reduced if water pressures are lowered using pressure management.
District Metering and Pressure Management
Water networks can be monitored more effectively for leakage if the network is broken down to smaller areas. This is called network sectorization and involves the setting up of District Metered Areas (DMAs). In conjunction with this exercise, the potential for pressure management should be examined so that the network changes are made in a coordinated way. A network model should be used to validate the proposed changes before implementation, and when network changes are made, the entire exercise needs to be carefully managed.
Active Leak Detection
In order to reduce water losses, it is essential to have an effective response when water leaks need to be located. There are different approaches adopted by water suppliers and leak detection companies; the important issue is that leaks are located in a timely manner and then repaired without delay. Performance based leak detection contracts can be used to ensure leak detection work is cost effective and achieves the desired results.