What Are the Alternatives to Damming Rivers?

The era of widespread construction of large dams for the most part ended in the 1960s and ‘70s.  Or so we thought.  Recently, numerous proposals for new dams have emerged, mostly in the name of improving water supplies strained by urban growth, a desire to irrigate more cropland, or adapting to expected changes in precipitation patterns accompanying climate change.  But new dam proposals don’t have to signal a new dam building era – in the vast majority of cases, water supply alternatives, such as water efficiency and conservation, will prove less costly for taxpayers, rivers, and communities as a whole.

Different Dams, Same Problems

Not all new dam proposals involve traditional dams blocking major rivers – many would dam side canyons or tributary creeks, relying on pumps from a larger river to store water for times of year (typically summer) when more water is desired.  These off-channel dams share many of the environmental drawbacks associated with traditional dams: they may block fish migration, harm water quality and temperature, flood valuable riparian and terrestrial wildlife habitat, and reduce or alter river flows.  And like traditional dams, off-channel dams can cost billions of taxpayer dollars to construct.  Off-channel dams can also use a lot of electricity — typically more than they can generate by releasing water – as water usually needs to be pumped uphill to fill their reservoirs.  In dry years, the water needed to fill a reservoir may not be available, and if there is water available, much of it will evaporate (an increasingly serious issue as summers grow hotter).    

That said, there may be cases where a new off-channel dam makes sense, and could actually help improve seasonal flows for fish and recreation in a nearby river.  More often than not, however, the environmental and economic costs of a new dam – whether on- or off-channel – will outweigh any benefits.  That’s why the potential of demand reduction strategies and alternative sources of water supply must be thoroughly analyzed and, if there is potential to meet demand, implemented before a new dam proposal receives serious consideration.

So Many Dam Alternatives

Dams are hardly the only way to meet demand for water, whether it’s new demand due to population growth or to adjust to altered precipitation or runoff patterns resulting from climate change. 

The first step in fighting a new dam is to insist that a reasonable assessment of demand for water is made available.  Without knowledge of how much water is needed, discussion of tools to meet demand is premature.  Any credible demand assessment should assume future implementation of significant conservation and efficiency measures

Once demand is nailed down, citizens should call for a thorough assessment of supply options to meet that demand. 

Water Efficiency = Water Supply

  • Water efficiency and conservation are the simple, proven, cost-effective, and immediate ways to secure new supply and should always be the first options examined. In the Southeast, on average water efficiency costs $0.46 – $250 per 1000 gallons saved while dams cost $4,000 per 1000 gallons of daily yield. Communities can also avoid or defer significant infrastructure costs through investing a fraction of the money in water efficiency measures as Seattle did when, in the late 1980s it started investing in water efficiency as water supply and avoided $100 million in long-term water supply costs by investing $30 million in water efficiency

Other Supply Options:

  • Reuse: Also known as water recycling or reclamation, water reuse refers to the use of treated sewage, graywater, or stormwater for non-potable purposes such as irrigation, industrial processes, fire protection, toilet flushing, among others. Drawbacks of this option can include costs associated with a municipal scale dual distribution system, and water that would have otherwise returned to the source river/water body once treated is now designated for a consumptive use, in the case of irrigation, that will not return to the river and may result in decreased flows.
  • Groundwater recharge: This involves recharging underground water sources during a wet year or a season (often winter) when water is available.  Drawbacks of this option can include costs associated with pumping and piping infrastructure, and the effect on instream flows when water is pumped from a river. 
  • Re-operation of existing dams:  Changing the way an existing dam is used is typically cheaper and less environmentally harmful than building a new dam, and in some cases re-operating a dam can provide water for cities, farms, and fish during critical times of year without major environmental, energy-production, or flood protection drawbacks.
  • Water markets:  In the western U.S., systems that allow for the buying and selling of water rights can, along with conservation and efficiency, help extend the ability of existing water supplies to meet challenges presented by growth and climate change. 

In most cases, these water supply tools, whether alone or in combination, will prove far less expensive than building a new dam.  These tools also tend to be more flexible than surface storage dams when it comes to adapting water supply systems to a changing climate.  For instance, unlike traditional surface storage solutions, conservation, efficiency, groundwater storage, and western water markets are not vulnerable to increased evaporation as temperatures rise.  In addition, conservation and efficiency can be implemented anywhere.  New storage projects, on the other hand, only benefit those located within a certain proximity. 

Tools to Slow a Bad Dam Proposal’s Momentum

In addition to insisting on credible evaluations of water demand and water supply alternatives, citizens should call for any studies of new dams to include ample opportunity for public input, ideally well before it goes through the official federal or state environmental review process.  Ample opportunities for public input will allow the public to expose any faulty assumptions regarding demand and supply evaluations as well as any other environmental and economic problems.

Another thing citizens should insist on is that the beneficiaries of a dam pay for its benefits.  Support for a dam can drop off considerably if local water users – who often envision new dams as pork barrel projects paid for by federal or state taxpayers – have to shoulder the burden of dam construction themselves.  In some instances, such as when public utility is proposing a new project, the user pays principle will likely be followed out of necessity.  But user-pays is a somewhat novel concept when it comes to large western water storage dams that are operated largely for the benefit of the irrigated agriculture industry, but paid for primarily by taxpayers. 

Case Studies

  • Black Rock Dam – Wrong Dam, Wrong Approach:  The Black Rock dam proposal, which would construct a 700 foot dam in an intermittent creek valley between the Yakima and Columbia rivers in south-central Washington state, is an example of how not to approach a dam proposal.  Here, the local congressman, at the behest of local irrigators and developers, succeeded in obtaining authorization for a federal study comparing building Black Rock dam to doing nothing – an artificially restrictive set of options that did not include a full examination of alternative supply tools.  On top of that, the federal agency that performed the study failed to include aggressive conservation in its demand projection.  Fortunately, the project is likely to die of its own weight, as it could cost over $7 billion and carry a risk of seeping into radioactive groundwater beneath the Hanford Nuclear Reservation, reducing the ability to contain that groundwater before it contaminates the last free-flowing stretch of the Columbia River.
  • Crab Creek Dam – Wrong Dam, Right Approach:  Across the Columbia River from the Black Rock site lies Crab Creek, the longest creek in the United States, and a small but biologically important population of threatened steelhead trout.  A recent appraisal evaluation by the Bureau of Reclamation and the State of Washington identified the lower Crab Creek as a potential site for a new water storage dam.  Thanks to the efforts of American Rivers and other conservation groups as well as the requirements of a state water management law [link to it], Washington state has agreed to provide a comprehensive analysis of water demand and water supply alternatives before deciding whether it makes sense to pursue the Crab Creek dam proposal further.  The Crab Creek proposal is not dead yet, but the process currently underway is likely to show decision-makers that there are cheaper, more environmentally friendly ways, including efficiency and re-operation of existing dams, to meet central Washington’s in- and out-of-stream water needs.
  • Connecticut River Dam – Back to the Future:  In the mid-1980s Boston was faced with the question of how to secure its water supply for a growing city.  They examined many supply-side options including damming the Connecticut River.  After evaluating all their options, the Massachusetts Water Resource Authority (MWRA) decided in favor of aggressively pursuing water efficiency and against the damming of the river.  Shortly thereafter MWRA initiated its conservation program which included a leak detection and abatement program, system-wide residential retrofit programs, changing the state plumbing code from 3.5 gal/flush to 1.6 gal/flush, and industrial audits.  Boston successfully secured its needed water supply by reducing its water consumption from 330 million gallons per day in the mid-80s to 205 million gallons per day in 2009, a 35% reduction. In fact, the metro area now uses less water than it did in 1911. And while they spent $40 million on these water efficiency measures, given that they were able to avoid the $500 million cost of the dam, overall water efficiency was by far more cost effective.