While demand for drinking water is increasing, the water levels of many catchment areas are dropping at an alarming rate. Groundwater exploitation rates are often over recharge capability and there is an increasing risk of source pollution, depletion and permanent hydrogeological damage.
If systems are unstable, water dispersion and network failure rates rise sharply, leading to excessive water loss. In such cases, restoration is of little help unless the dynamic efficiency of the network is first improved. Pumping, sanitation and the partial distribution of water extracted unnecessarily, along with repair and maintenance work, add to environmental damage.
The project was located in the Arno river plain, upstream of the town of Pisa. It includes a significant water district consisting of some 1 000 km of network pipes supplying water to nine municipalities. Approximately 95% of the water resources come from wells that withdraw around 17 million cubic meters of groundwater from the Bientina aquifer, where over-exploitation has triggered in the last few years a significant decrease of piezometric heads (water pressure measurement) accompanied by subsidence phenomena and worsening of water quality.
The A.S.A.P. project aimed to demonstrate the economical and technical viability of a procedure for preventing the over-exploitation of groundwater systems. This would be achieved through an integrated approach to optimising networks that combine technologies such as leak detectors, GIS and modelling systems and simulators.
The aim was to reduce extraction from the demonstration system by 10% and to reverse the current decline in the water level from -0.5 m/year to +0.5 m/year, so that it would return to the level it had in the year 2000. The project also sought to reduce the likelihood of low-quality water and pollutants migrating into freshwater, as a result of changes in groundwater flow patterns from adjacent systems. Pumping would be reduced as far as possible, without compromising the quality of water even in periods with strong seasonal fluctuations in demand.
1) The project carried out the following preliminary actions: -Analysis and modelling of the abstraction and water supply systems; and -Assessment of hidden leakages in the network, as well as of the quantitative requirements to achieve the improvement targets. This, together with a risk assessment, enabled the team to identify and prioritise the main interventions to be carried out on the water supply network.
2) The next stage involved: - Hydraulic modelling of the network (by zones) in order to best locate pressure control valves (followed by installation of the valves and analysis of relevant data); and - Detection and repair of significant leaks and pressure regulation of the network.
3) The next stage was the main monitoring stage involving: - Real time data collection of network pressures and flow rates as well as of aquifer piezometric heads; and - Re-calibration of the hydraulic model and of the remote control system through dynamic feedback between the two. In this way, hidden leaks became promptly visible and easy to pinpoint in the supply process. This enables a significant reduction of water abstraction and related impacts on the environment.
Summarised in a protocol (available in English, Italian and Spanish), this innovative methodology has been widely disseminated and has generated considerable interest among public administrators, professionals and managers involved in water management.
- Financial resources for bulk reconstruction and/or restoration of water networks are rarely available. More usually budgets are only sufficient to cover annual maintenance, plus limited amounts for ongoing repairs. The project protocol however, is able to convert even limited resources into effective action plans for efficient abstraction and reduction of leakages.
- Dynamic flow/pressure regulation based on reliable network modelling enables management of priority actions and remediation, ensuring the most suitable responses to demand fluctuations or displacements.
- Diminished pumping needs, accompanied by robust aquifer modelling and data, enables the most efficient allocation of available groundwater resources. Moreover, the appropriate reduction of abstraction enables piezometric pressure to be increased, thus allowing aquifers to regain equilibrium. Additionally, the rise of piezometric pressure is accompanied by diminished diffusivity with a subsequent reduced risk of induced infiltration, or migration or intrusion that potentially exposes groundwater to pollution.
To summarise, the project exceeded its overall goal of reducing water abstraction by 10% - attaining a value of 15%. This has been verified on data series for 2006 (baseline), 2007, 2008, and 2009. Figures showed a progressive reduction of pumping by some 1.5 million cubic metres/year (equivalent to the annual average consumption of 11 000 families).
As a result, the negative drawdown trend of the piezometric level was reversed with an average build up of + 0.3 m from 2005 to 2008 and peaks ranging from 0.5 to 1 m. This is expected to also have a positive impact on the quality of the water, thanks to a reduced vertical migration of surface, low-quality water and pollutants (reduction of vulnerability).
Taking 2006 as a reference point, power consumption in kWh/ year was around 9.38% lower in 2007 and 12.81% lower in 2008.
The A.S.A.P. Protocol was included in the White Paper "A Strategy for Water Supply in Tuscany" published in June 2008 by the Cispel Confservizi - Tuscany Water Commission - as a best practice for intervention strategies to address water emergencies.
Finally, the A.S.A.P. project was awarded in 2009 under the CEEP-CSR label. The awards, managed by CEEP ? the European Centre of Enterprises with Public Participation and Enterprises of General Economic Interest, recognise good practices in the field of Corporate Social Responsibility (CSR).Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).