MASTERPLAN TOOLS FOR WATER SUPPLY NETWORK

K. Odeh (1), F. Fotoohi (1), P. Feron (2)

(1) Lyonnaise des Eaux – CIRSEE (Centre International de Recherche sur l’Eau et l’Environnement), 59, Avenue Emile Thiébaut, 78110 Le Vésinet, France. Email: ,

(2)Lyonnaise des Eaux – SAFEGE (Société Anonyme Française d'Etudes et de Gestion), B.P. 727, 92007 Nanterre Cedex, France. Email:

ABSTRACT

In this paper we propose decision-making tools for strategic development planning of drinking water production and distribution system in order to best meet future needs and to guarantee a high reliability. These tools gather and organise all the information required for a masterplan study and facilitate the follow and the update of the master plan.

KEYWORDS:Masterplan, reliability, drinking water, planning, software

Introduction

The adaptation of production, storage and transport system of a drinking water network for the future needs is complex. In the scope of optimising the masterplan, Lyonnaise des Eaux – CIRSEE has develoed a global approach in order to minimise long term investment costs and to improve network operating safety. We propose decision-making tools to establish and update the drinking water masterplan (BOSD) and to evaluate quantitative and qualitative risk indicators in order to compare the safety of different investment scenarios (SURETE) [1].

To achieve this goal, a set of complex parameters and interdependent constraints are taken into account in order to:

  • Meet future water needs (peak demand),
  • guarantee the quality of the distributed water,
  • minimise investments and operational costs.

The Masterplan Toolbox is a study and simulation tool for use by engineers dealing with new works, and engineering and design offices responsible for monitoring and updating drinking water strategic plans. It provides the users with a toolbox to:

  • Gather and organise all the information required for drawing up and updating the strategic plan,
  • define and evaluate various development scenarios for the production and distribution system,
  • present the investment solutions and work-plans using an adequate presentation support and material.

Approach and Functions

The approach used by Masterplan Toolbox is based on the following description:

Masterplan Toolbox Approach

The masterplan toolbox includes the following functionality:

Description of the production and distribution system and projects:

  • The user builds a macroscopic model of the system to be studied by positioning icons representing sub-networks, plants and production units on-screen and connecting them using the adequate links. The user then has to describe the physical characteristics of equipment items. New projects (production plants, reservoir and trunk mains) are described in a similar manner.
Network and installations definition

Sizing goals:

  • The software allows the user to define the peak consumption coefficient (study tool is used to calculate this coefficient) and levels of the losses per sub-system. It allows the strategic plan objectives and goals concerning consumption levels and storage capacities to be set. The level of consumption to be met depends on average consumption and the peak coefficient. The storage goal is expressed as percentage of average network consumption.

Goals and parameters definition

Updating water demand:

  • This module is used to update historical consumption files and to forecast the water demand for different geographical areas. Data access is facilitated by a cartographic presentation of sites

Water needs update

Project definition and planning:

  • The user-friendly interface enables planning of strategic plan projects over several years. At any time, a set of basic indicators (demand/resource and storage balance sheet), investments and works schedules) enable evaluation of project coherence and ensure that the retained solutions meet the masterplan objectives.

Project scheduling and scenarios

Diagnostics:

  • This step allows diagnosis of the coherence of proposed solutions by taking into account the transport capacities of the network. A simulation method is implemented to identify weak and define multiple overall indicators.

Water resource balance sheet

Masterplan validation in term of reliability

The Masterplan Tool Box is jointly used with a risk assessment tool (SURETE) which calculates reliability measures for a water supply network:

  • Availability (1- probability of water shortage)
  • Number of unavailable days over 1000 days network operation
  • Average water deficit over 1000 days network operation
  • Cut set : components set where failure generates water shortage

These indicators enable the evaluation of investment scenarios issued from Masterplan Toolbox in terms of reliability and security. Vulnerable parts of the network are identified by analysing minimal cut sets.

The methodology used is based on stochastic flow reliability model. We evaluate the probability that a water distribution system can meet a required water flow level at each demand point. Approximation techniques based on Shannon factorisation have been implemented in order to reduce time execution for large networks[2].

Conclusion

The Masterplan Tools are high-tech software designed to measure new works for civil engineer and planning departments in charge of drinking water masterplan studies.

They take into count a complex set of objectives and interdependent constraints in order to establish and to follow-up evolution scripts capable to satisfy future water needs from a quantitative and a qualitative point of view and guarantees a high reliability of the water system.

References

Odeh, K., Fotoohi, F. & Feron, P. (1999). Risk assessment tool for water supply network. CCWI’99 Exeter, Septembre 1999.

Schon, W., Odeh,, K. & Denoeux, T. (2000). Maîtrise des risques dans le domaine de l’eau potable. Lambda Mu 12, Monpellier, Mars 2000.