The Importance of EstuariesBy Harry Branch For many centuries the Deschutes Estuary provided vital ecological functions for a wide range of biota including numerous salmon that spawned in streams located within the boundary of the estuary. The openings or estuaries of these individual streams, Percival, Schneider, Ellis, Indian and Moxlie creeks, were the locations of villages of between fifty and one hundred Salish People, who chose stream estuaries for their homes because they were productive food sources and tied into the uplands. The Deschutes River itself had no historic salmon runs because a large waterfall at the head of the estuary now known as Deschutes Falls blocked their migration. In 1896 the Olympia Brewery was established at the head of the Deschutes Estuary. Ships navigated the estuary at high tide and tied to a dock at the brewery to load and unload supplies and products. The dock was located in deep water, scoured by the waterfall. The old brewery still remains, falling into disrepair. In 1951 the estuary was dammed forming the 260-acre Capitol Lake. For its first fifty years the lake was relatively trouble free. By the beginning of the 21st century the lake had largely filled with sediments and the shallow environment periodically became home to invasive plants that required chemical eradication. In October of 2009, New Zealand Mud Snails were discovered in Capitol Lake. These small snails reproduce asexually, each snail producing as many as 230 offspring per season. The snails typically out-produce native species. They prefer fresh water but can tolerate salinity of 15/ppt well and 35/ppt for short periods. They will not tolerate repeated or extended immersion in marine waters. *What's so important about estuaries? Nutrients entering marine waters are consumed by marine plants called algae, especially free swimming algae called phytoplankton. When too many nutrients enter some systems, phytoplankton overproduce, die and rot, creating first a spike then a drop in dissolved oxygen and the water becomes anoxic. Ironically, when working properly, phytoplankton create not only dissolved oxygen but much of the earth's atmospheric oxygen. Phytoplankton are also the primary producers, the base of the food web. Hundreds of years ago when thousands of salmon died and rotted in area streams, these streams were loaded with nutrients. Given the right conditions the marine environment has a tremendous capacity to digest nutrients without becoming anoxic. Almost any plant or animal without some control on its abundance will overproduce. The natural control on phytoplankton abundance is the grazers or herbivores, mostly tiny crustaceans called copepods. In a healthy estuarine environment, there's a mix of phytoplankton and herbivores. A natural estuary is characterized by a long shallow run out. The tide flowing in and out through a vast network of tide flats and channels twice each day brings herbivores well up into the system where they can control the production of phytoplankton. Structure is the most basic oceanographic parameter and estuaries have very particular structures. Southern Budd Inlet used to be a highly productive ecosystem teeming with eelgrass, seaweed, herring, smelt and other fish and diving and wading ducks. We've filled some places and dredged other places and beach and salt marsh are now rock and concrete. Removing the dam will instantly increase the area of the estuary by a third. There will almost surely be a corresponding increase in the richness and abundance of life. Levels of dissolved oxygen will stabilize. Isn't an estuary smelly? In the early 20th century the area along the eastern shore of what is now Capitol Lake was the location of a shanty town known as Little Hollywood. The shanties were not hooked to a sewer, resulting in a nasty smell that many local people still associate with estuaries. Naturally functioning estuaries actually smell good, largely because they generate large quantities of atmospheric oxygen. Will the idea of a reflecting pond be lost with an estuary? At high tide the area will look much as it does with the lake. At low tide we will see tide flats like we see in Ellis Creek at Priest Point park, frequented by Dunlin, Blue Heron and perhaps other species including flat fish and shellfish that might someday be harvested for food. Some animals will not be seen as frequently, including insects that spawn and live in fresh water and birds and bats that feed on these insects. What are the comparative costs of maintaining the lake versus restoring the estuary? The costs of each have not been firmly established but certain things are known. If nothing is done, the lake would continue to fill with sediments and pass through various marsh or "swamp" incarnations. Dredging would fix some problems but would need to be repeated periodically. There is little or no outside funding for the lake option; no state or federal agencies have come forward and conservationist groups are wary of the lake because of potential problems like the spread of invasives. A dredge cannot simply be moved into place with tugs but must be constructed on site; it would be difficult and expensive. Dredge spoils must be moved at least twice, from barge to barge, or barge to truck or rail car, or pumped through long pipes. There are federal and state funds available for estuary restoration. Conservationist organizations are looking for exactly this kind of project. The Army Corps of Engineers is equipped to do the work and is mandated to maintain the shipping channel as far as and including the Marine Terminal. Natural systems, like estuaries, are inherently self maintaining. Over time, there will be a balance of deposition and erosion of sediments and the estuary will find a stable structure that will gradually expand over thousands of years. The only maintenance will be periodic navigation dredging. Will Budd Inlet fill with sediments eliminating the Yacht Club, marinas and the Marine Terminal? A high resolution aerial photo taken of Budd Inlet in 1936 clearly shows deep water following a serpentine pathway through the estuary. Places in Budd Bay that are now occupied by marinas, were all occupied by marinas long before the existence of Capitol Lake. Removal of the dam will return the bay to this original configuration, and would not impact marina activities. What is the current status of the lake? During summer months, much of the lake is covered with a proliferation of green colored fresh water algae. Portions of the lake are fenced and posted with warnings to keep people and pets away from the New Zealand Mud Snails,which are readily spread on everything from dog feet to bird droppings and could easily spread to nearby streams and lakes. Back-flushing the lake with salt water has failed to kill off the snails and chemicals that might kill them would kill native species too. There may be no acceptable way to get rid of the snails, other than getting rid of the lake. Time will tell. If we do clear the lake of them, what's next? This is always the question with an unnatural, out-of-place, place. Harry Branch is a member of DERT, the Deschutes Estuary Restoration Team. The group's mission is to facilitate discussion and raise community awareness of the advantages inherent in a naturally functioning estuary. As our knowledge of Capitol Lake continues to evolve, DERT is convinced that our community will come to realize that restoring the lake to an estuary makes the best ecological and financial sense for ourselves and future generations; maintaining it as a lake is an expensive and unrealistic option. Check out DERT's website, join, or make a donation at: http://www.deschutesestuary.org
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