The Environmental and Economic Costs of Irrigated Agriculture

The Unsustainability of Irrigated Agriculture

Irrigated agriculture is highly unsustainable due to its environmental costs. These costs include reducing river flows and aquifer levels (especially during dry periods), severely impacting ecosystems such as wetlands. Furthermore, irrigation introduces nutrients and pesticides to the environment, the full effects of which have not been adequately measured. Currently, the balance between advantages and disadvantages leans heavily toward the latter.

The problems generated by irrigation are often presented generically, failing to reflect the depth of these issues. This generic presentation is often a reaction to a lack of understanding regarding the environmental aspects of irrigation. Therefore, it is crucial to clearly define these problems to find the best solution for each specific challenge.

Key Environmental and Economic Challenges of Irrigation

Some of the stated problems include:

• Ecosystem Destruction: The destruction of valuable ecosystems, such as those substituted by rainfed agriculture, which often possess much higher biodiversity.
• Modification of River Flows: The destruction of entire flood valleys (e.g., the Rialp project) and the definitive modification of river flows without thoroughly studying the implications. The current flow removed from the Segre channels regenerating Urgell is incompatible with maintaining the river's flora and fauna; its environmental flows are inadequate.
• Downstream Effects and Evapotranspiration: The water used for irrigation is largely evapotranspirated (often over 80%), meaning it does not return to the river. This severely affects the downstream flow. The Ebro River, for example, has lost nearly one-third of its volume in dry years, resulting in less than half of its natural regime.
• Groundwater and River Pollution: Irrigation pollutes groundwater and rivers, carrying high loads of nutrients and salts. These inputs are responsible for poor water quality downstream. Specifically, the Ebro River has a salt content almost twice its natural level due to irrigation practices.
• Pesticide Contamination: The contribution of pesticides (e.g., Atrazine) to aquatic systems is highly significant and affects the entire food web. These and other pesticides are routinely detected in our rivers and wetlands.

Economic Inefficiencies and Water Pricing

• Low Economic Contribution vs. High Water Use: From an economic perspective, irrigation contributes only about 2% of regional revenue and employs a similar number of people, suggesting it is not economically relevant relative to its resource consumption. In contrast, it consumes 70% of the water in Catalonia (up to 90% in western lands).
• Subsidies: Critical economic subsidies are also a major issue. Many businesses and other economic activities receive no subsidy for their operations, highlighting an imbalance in resource allocation.
• Water Pricing: The incredibly low price of water is also criticized, as it actively discourages the increase of efficiency and conservation efforts.