Natural ecosystems, when healthy and functioning well, are vital to the economy. Healthy watersheds, wetlands, floodplains, and river systems store and cleanse our water supplies and control floods naturally. Nature’s services recharge groundwater with the natural flow of rivers and their floodplains; coastlines are replenished and soil is enriched. Kids can harvest water right where they live and use the water for their fruit and veggie gardens by attaching a rain barrel to the down spout from their roof. By using native plants rather than a lawn, contouring the landscape, making curb cuts from the street, and building swales, homeowners can harvest an abundance of rainwater on site.
However, the ability of freshwater swamps and river floodplains to store water, mitigate floods, and break down pollutants is stopped by levees and dams. Instead, floodwaters rush down the canals, reducing groundwater, removing the natural cleansing process, erasing habitats for birds and fish, and causing downstream flood risks. Rivers bearing high loads of nitrogen from chemical fertilizer runoffs that wetlands might otherwise absorb have contributed to the creation of more than 400 low-oxygen dead zones in coastal bays and estuaries around the world. Soils depleted of microbes and organic matter due to conventional agricultural practices no longer hold moisture for the plants and crops. Rain water runs rapidly over pavement that covers urban and suburban landscapes and, instead of soaking into the land, floods homes and pollutes creeks and bays.
Our engineers bulldoze, dike, and drain away Nature’s services by constructing dams, canals, and treatment plants to block and divert rivers. Dams and reservoirs used to store water, divert about 35% of river flows, trapping billions of tons of sediment that would have been carried to the sea to replenish the coasts, as a result, productive deltas, from the Nile to the Mississippi, are losing ground to the sea. The freshwater plants and animals are headed to extinction five times faster than the land species. Blending engineering, ecology, and economics into a holistic approach that recognizes the value of Nature’s services, our engineers can work with nature to rejuvenate watersheds and floodplains, and replenish rivers, soils, and groundwater.