Assessing impacts on irrigated agriculture using an ecosystem-based approach in a Mediterranean reservoir/lake

• An ecosystem-based approach is being evaluated in an irrigation reservoir/lake. • Modelling is supported by a detailed crop dataset and irrigation methodology. • An irrigation deficit of up to 30% occurs when adopting the ecosystem approach. • Climate change is expected to have a lesser impact on irrigated agriculture. • Water policies are needed to ensure food production and environmental protection. Water management policies that support environmental conservation are expected to affect irrigated agriculture. In addition, the impact of climate change on agricultural productivity is also pivotal, as it can further affect water availability. This paper investigates two water level management scenarios at Lake Kerkini, a multipurpose reservoir/lake in Greece, using the MIKE HYDRO Basin modeling system to simulate the variation of lake’s water level and the water demand deficit in collective irrigation networks. The first scenario (S1: BAU) represents the business-as-usual water management plan, while the second scenario (S2: ECO) is based on the ecological needs of Lake Kerkini ecosystem. Additionally, two other scenarios are examined to assess the impact of climate change on both the business-as-usual (S3: BAU-CC) and ecosystem-based approach (S4: ECO-CC). Under the ecosystem-based approach scenario (S2), the irrigation water requirements (IWR) of networks supplied by Lake Kerkini are not fully met, resulting in an increased water demand deficit from above 10% and up to 30%, compared to the business-as-usual scenario (S1). Due to climate change (S3 and S4), the deficit in irrigation networks is increased by almost 10%, compared to the corresponding scenarios without considering the impact of climate change (S1 and S2). As the irrigation deficit is expected to affect the yield of various crops and, thus, jeopardize food production and the net profit for farmers, this research provides valuable insights for decision-makers, highlighting the need for sustainable water management practices that balance agricultural productivity with environmental conservation.