By Guest Columnist SANDY TUCKER, Georgia field supervisor for the U.S. Fish and Wildlife Service

Atlanta sits near the headwaters of every river it depends on. It’s the nation’s largest metropolitan region, with the smallest area from which to pull water.

Without the water storage provided by Lake Lanier on the Chattahoochee River — and to a lesser extent, Lake Allatoona on the Etowah River — metro Atlanta could not have grown its current population of more than 5 million.

So it’s easy to understand why leaders say we need to build more reservoirs to ensure future water supplies. And we do. But not just anywhere, and not before pursuing options that are both less expensive and less damaging.

The cost of a new reservoir is considerable. Land must be purchased, sometimes from unwilling sellers. Houses, vegetation and other obstacles must be removed. Powerlines and other essential facilities must be relocated. Federal law also requires reservoir builders to compensate for the loss of wetlands and free-flowing streams by protecting similar wetlands and streams, in the same watershed if possible.

Reservoirs also reduce the amount of water available to downstream communities. On a hot summer day, millions of gallons of water evaporate off Lake Lanier.

In addition, dams significantly impact aquatic communities and can negatively impact downstream property. They isolate populations of fish and other aquatic species, cutting them off from their historic ranges. Dams also alter the natural river flows, often causing severe streambank erosion for downstream homeowners and degrading water quality.

When a dam is being proposed, the U.S. Fish and Wildlife Service must be consulted on impacts to wetlands, aquatic species, federally protected species and other fish and wildlife that depend on free-flowing streams. Our job is to minimize the damage to these natural resources by suggesting alternatives and ways the reservoir builders can compensate for impacts.

Water conservation tops our list of alternatives. We believe there’s much more our communities can do, from recycling gray water to aggressively repairing or replacing leaking pipes.

Other solutions, and there must be multiple solutions, include increasing storage capacity in existing lakes by removing sediment that builds up over time, and raising dam heights. Enforcing federal, state and local laws intended to keep dirt out of our streams would also maximize lake storage.

Another potential solution is turning old quarries into water-supply lakes. However, as with dams that are built on small streams, a lot of water must be pumped from somewhere. We would need to be careful not to dewater stream reaches or otherwise degrade the water quality in the source river.

When we do build new dams, let’s do it on streams that have already been irreparably altered, such as the Chattahoochee River below Lake Lanier. And let’s minimize the transfer of water from one river basin to another. Transferring water reduces downstream flows for the donor basin and alters the natural ecology of the receiving basin.

One much discussed proposal is to build a reservoir in the Etowah River Basin in North Georgia, at least partially on property owned by the City of Atlanta called Dawson Forest. The dam would impact three threatened and endangered fish. Two of them, the Cherokee and Etowah darters, are found nowhere else in the world. These fish live in shoals, which are shallow, cobble-bottomed river stretches. They cannot survive in lakes.

Our team of biologists in the Georgia Field Office pledge to work with state and local leaders to find better options. We believe there are less costly alternatives to damming a free-flowing stream — less costly to our pocketbooks and our natural resources.

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