Beneficial effects on water management of simple hydraulic structures in wetland systems: the Vallevecchia case study, Italy

• Published in: Water science and technology 2011-01, Vol.64 (1), p.220-227
• Main Authors: Carrer, G M, Bonato, M, Smania, D, Barausse, A, Comis, C, Palmeri, L
• Format: Article
• Language: English
• Subjects: Agricultural management; Agricultural pollution; Agriculture; Aquatic ecosystems; Artificial wetlands; Case studies; Coastal waters; Coastal zone; Coastal zones; Conservation of Natural Resources; Construction; Drainage basins; Drainage systems; Drought; Ecosystem services; Environmental monitoring; Eutrophic waters; Eutrophication; Freshwater; Hydraulic structures; Hydraulics; Intrusion; Irrigation water; Italy; Nonpoint source pollution; Nutrient loading; Nutrient removal; Nutrients; Outflow; Rain; Rain water; Saline water; Saline water intrusion; Water management; Water Movements; Water pollution; Water Pollution, Chemical - prevention & control; Water Purification; Water Quality; Water resources management; Water scarcity; Water storage; Wetlands
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2011.623

Conflicting water uses in coastal zones demand integrated approaches to achieve sustainable water resources management, protecting water quality while allowing those human activities which rely upon aquatic ecosystem services to thrive. This case study shows that the creation and simple management of hydraulic structures within constructed wetlands can markedly reduce the non-point pollution from agriculture and, simultaneously, benefit agricultural activities, particularly during hot and dry periods. The Vallevecchia wetland system is based on a reclaimed 900 ha-large drainage basin in Northern Italy, where droughts recently impacted agriculture causing water scarcity and saltwater intrusion. Rainwater and drained water are recirculated inside the system to limit saltwater intrusion, provide irrigation water during dry periods and reduce the agricultural nutrient loads discharged into the bordering, eutrophic Adriatic Sea. Monitoring (2003-2009) of water quality and flows highlights that the construction (ended in 2005) of a gated spillway to control the outflow, and of a 200,000 m3 basin for water storage, dramatically increased the removal of nutrients within the system. Strikingly, this improvement was achieved with a minimal management effort, e.g., each year the storage basin was filled once: a simple management of the hydraulic structures would greatly enhance the system efficiency, and store more water to irrigate and limit saltwater intrusion.