Development of Tools and Strategies for Controlling the Zebra Mussel in Pressurised Irrigation Networks

Abstract

Chemical products, mainly chlorine, are often used to control or eradicate the Zebra Mussel, Dreissena Polymorpha, in pressurised irrigation pipes, although other disinfectants have been used, such as hydrogen peroxide. An optimum application of these substances is essential to achieve maximum effectiveness at minimum cost, without harmful effects on crops or the environment. This work defines tools and techniques for satisfactory process design, taking into account the specifics of operation and flow structure in irrigation system networks (very different from those of domestic water supply), the species to be combated and the high concentration of organic material in irrigation water. New specific functions have been implemented and applied in GESTAR 2010 (www.gestarcad.com), the software application for designing and managing pressurised irrigation networks, facilitating the use of the urban network water quality simulation module from the EPANET2 programme, adapting it for these purposes and obtaining predictions for the evolution of the concentration of the additive used over time at all points in the network, considering the reaction in the raw untreated water supply and the reaction with the wall, due to the effect of interaction with the invasive mollusc species (not necessarily zebra mussel). 1. - INTRODUCTION AND OBJECTIVES. The Zebra Mussel (Dreissena polymorpha, Pallas) in continental water taken for use in irrigation systems has a devastating effect on these systems, adhering to pipelines and hydraulic infrastructure, leading to a significant increase in maintenance costs and loss of efficiency, blocking filters and taking hydrants out of service. The first populations of zebra mussel in the Ebro basin (Spain)were detected in July 2001, in the Flix reservoir. The population explosion of Dreissena polymorpha once it is introduced, reaching very high population densities, makes it practically impossible to stop the gradual colonisation of the different natural and artificial substrates in contact with the river. This threat to river ecosystems presents a serious risk of ecological and socio-economic disaster in the short and mid term