Neff’s Canyon Debris Basin & Dam

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Salt Lake County
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Salt Lake County
Preserve Neff's Canyon





A Salt Lake County flood control initiative is brewing into a major conservation issue. Salt Lake County is proposing that a debris basin and dam at the mouth of Neff’s Canyon be built.  Neff’s Canyon is between Millcreek Canyon and Mount Olympus. Although described as a “canyon”, it can be more accurately described as a Wasatch drainage area with its mouth at the top of the Olympus Cove residential area. With the exception of the remnants from an old small irrigation reservoir, it is wild and untrammeled. Within a few hundred yards of the mouth, one passes into the Mount Olympus Wilderness Area. This project would be located on Forest Service property, which will require a special use permit and an environmental assessment.  It would be a mistake to think that the Forest Service will resist this project. It will not. The Forest Service has already set a precedent by allowing a similar retention basin and dam be built at the mouth of Farmington Canyon in Davis County.

This proposed debris retention basin and dam would have the footprint of three full-size football fields, including the end zones. The dam face for this basin would be upwards of 30 feet high and stretch 800 feet long. All the vegetation within this area will be stripped bare. It is estimated that over 3,500 truckloads of trees, other vegetation, soil and rock would have to be excavated from the site. The finished project would remain perpetually void of any meaningful vegetation.

One of the County’s responsibilities is flood control. Look at your property tax notice and you will see a levy for flood control.  Neff’s Canyon represents a potential flood source risk in the event a very unlikely set of circumstances come together at the same time -- an example being a 100 year thunderstorm saturating a fire-denuded hillside. In 1980 the Federal Emergency Management Administration  (FEMA) designated a small section of Olympus Cove as being a “Flood Zone A”, which means there is a certain probability that within a hundred year time span a flood is likely to occur. If you are a homeowner in this small area and need to secure a mortgage, the lender will require you purchase federal flood insurance.

The Mount Olympus Community Council, as a consequence of complaints from residents forced to purchase flood insurance on their homes, requested that the County come up with a plan to mitigate the flood risk. This past summer Salt Lake County pitched this project to the Community Council and interested residents. Community Council members were favorably impressed, as a retention basin and dam of sufficient size will cause FEMA to take away the “Flood Zone A” designation which in turn will eliminate the lender-mandated requirement that flood insurance be purchased.  The number of Olympus Cove homeowners who currently purchase federal flood insurance is unknown. What we do know is that all the homes within this Flood Zone A (about 150 out of a total of a 1,000 or more homes in Olympus Cove) each have a market value of at least $700,000. A number of these homes over the past few years have been purchased, torn down and replaced with what can only be described as McMansions. It is safe to say that in this affected area the requirement to purchase federal flood insurance is categorically not an economic hardship.

Opposition to the County’s debris basin and dam rapidly surfaced and with it came a change in the primary rationale for the project from “saving homeowners the cost of flood insurance” to one of  “safety”. The implication of this “safety” argument is that those in opposition are now cast in the light of being motivated solely by a “not in my back yard” mentality and indifferent to the larger issue of  “safety”.

Salt Lake County has by no means put forth any compelling arguments in favor of the project. The geology / engineering report produced by an independent consultant for the County is not exhaustive and lacks certain fundamental information. By no stretch of the imagination has the County proved that this retention basin and dam are critical to the safety and welfare of the County’s residents. Only a very few affluent homeowners will benefit from the avoidance of having to purchase federal flood insurance. If safety is a real issue, then there are number of alternatives that would have a much smaller footprint and be far less abusive. Fundamentally, a far larger constituency is being ignored – those who use Neff’s Canyon as a refuge from urban life and those who simply value an unspoiled Wasatch.

To the credit of County Mayor Corroon, he recently slowed the forward momentum of this project once he became aware of the growing opposition.  But he has not eliminated it. Instead, Mayor Corroon is looking for a community consensus before proceeding. Whether or not this project is killed, dramatically downsized or creatively changed to minimize its impact will depend upon which constituency is more vocal and puts forth the more compelling arguments.  Save Our Canyons is working to build a coalition with other environmental organizations in order to make this controversy a countywide issue and to maximize opposition and develop creative alternatives. Flyers are being distributed to Neff’s Canyon visitors and to local residents. By word of mouth more people are learning about this project. Activists / residents in Olympus Cove have created a website (http://isa.arborist.googlepages.com/saveneffscanyon). It is critically important that you now take the time to contact Mayor Corroon and other County’s decision-makers to express your opposition. Also, you need to alert your friends of this threat so that they too can take action.

In addition, the Mount Olympus Community Council will host a meeting at 7:00 PM on February 20, 2007 at the Churchill Junior High auditorium where those in favor and those opposed will have the opportunity to express their views. If the Community Council perceives a majority of the attendees are in favor of the project, there is an excellent chance the Community Council will formally endorse the debris basin and dam project. This endorsement will be the green light for the County to proceed with the design, engineering and permitting process. Your attendance at this meeting is quite important, as you can well imagine.

1.    Mayor Peter Corroon:  468-2500, or Mayor@SLCO.ORG
2.    Mark Crockett, Council person, 468-2937 or MCrockett@SLCO.ORG
3.    Ken Smith, Chairman, Mt Olympus Community Council, 278-4567 or kensmith@mtolympuscc.com
4.    Jeff Silvestrini, Vice Chairman, Mt. Olympus Community Council 277-0817 or jeffsilvestrini@mtolympuscc.com