Dammed If You Do

As the United States was colonized and the Manifest Destiny was realized more and more Americans began to settle out west. Many of these areas faced major difficulties in agriculture and turned to dams to provide drinking water and irrigation. This strategy was widely used through the 1980’s where large dams, were being constructed at a rate of about 500 per year. Now most rivers in the entire Northern Hemisphere have been dammed for hydroelectric power, water supply, irrigation and even for tourism. In fact, the Yellowstone River is the only one in the country with more than 600 miles of undammed water.

This may seem like a success from the power, water supply and irrigation standpoint but this large scale damming has had drastically negative effects in recent years, as highlighted by struggles in the Pacific Northwest. The New York Times has recently reported that all commercial fishing of the Chinook salmon in Northern California, Oregon and Washington state has been banned for the 2008 season, which started on May first. Due to extremely low numbers of young salmon making the journey upstream to mate there has been serious concern that the fishing industry may kill off the population. One potential reason for these low numbers of salmon has been attributed to the increased use and amount of dams.

As most people know, salmon are famous for being anadromous, meaning that they survive in both fresh and salt water. The fish are born in rivers and as they grow swim downstream to the ocean. Each year when mature, they return to their home rivers swimming upstream to lay their eggs. With the dams however this has become quite difficult. Immediately one would recognize that a dam put in downstream of a breeding area would make it virtually impossible for a salmon to make it upstream to mate. There are several other difficulties that the dams provide as well.

For one, dams not only stop the flow of water down a river but also halt the flow of silt and sediment. Though this seems to be no great loss for the river it in fact is exactly the type of environment the salmon like to lay their eggs in. Also the institution of irrigation systems disturbs many salmon habitats as many pooling areas are, in effect, vacuumed out to bring fresh water to agricultural hubs. Young salmon swimming downstream had been constantly sucked up these tubes and simply dumped in agricultural aqueducts. With no nutrients or resources these young salmon would be left simply to die NY Times.

It is time to recognize the damage caused by these dams in regions such as the Pacific Northwest and find a solution as quickly as possible. Many dams have been removed over the past few years in an attempt to free up both water and sediment, and there has been a movement to screen the tubes leading to irrigation ditches as well. However if this has led to such a large crash in the numbers of the Chinook salmon there is no reason that we should not find better ways to manage our ecosystem before this population becomes totally depleted.

Daniel O'Leary