DISRUPTION OF LOCAL WILDLIFE - During the time of construction, it is expected that the noise pollution will disturb the local wildlife found on the south slopes of Mt. Elden. Typical wildlife found in this area are gray foxes, coyotes, racoons, hawks, elk, and deer. However, it should be noted that this will be short term and is expected to no longer be disturbing to the local wildlife after the time of construction.
EROSION POTENTIAL - Water will be retained by check dams during storm event up to a day after which will help slow the overall velocity of runoff to reduce the erosion potential. Since the placement of the bioswales are at a relatively sloped area the erosion potential could increase. However, to counteract that, the use of check dams at every fifteen feet will help reduce the velocity of the runoff to ultimately reduce the erosion occurring downstream.
NATURAL CHANNEL - The backfill chosen for this design is made up of riprap which will help preserve the natural environment characteristics found in the Mt. Elden area, rather than introducing large foreign slabs of concrete. Native grasses and vegetation will be planted in bioswales to increase soil moisture in and around bioswale to encourage growth/provide a natural form of bank reinforcement.
COST OF IMPLEMENTATION - The existing stormwater infrastructure in the Shadow Mountain community includes limited storm drains and culverts as the residents in the area are relying on sandbags and plywood built up to slow down the flood waters from impacting their property. This cost of implementation is cheaper than other alternatives consider but could affect the city stormwater fee in order to pay for construction and maintenance. The city and residences of Shadow Mountain will spend less on flood prevention work and decrease the flood damage repair expenses.
TIME OF CONSTRUCTION - The anticipated construction of the bioswales will take a couple of months for completion. To prevent any conflict with the monsoon season, the time of construction will take place between the summer months of April through June to prevent the impact of future flooding. Completing construction during this time will reduce the impact of further flooding that could potentially increase the cost given the high volumetric flowrate.
MANPOWER - The manpower required to maintain the bioswale will be affected by the staffing abilities of the City of Flagstaff. The final design will require annual maintenance. The City of Flagstaff will need to have staffed individuals who are competent in maintaining flood prevention designs. The safety concerns identified for annual maintenance are standing water, sediment buildup, collapsed check dams, and wildlife. These concerns will need to be addressed and a safety plan will need to be created to eliminate the associated risk.
SHADOW MOUNTAIN RESIDENTS- The shadow mountain residents will be impacted by the new design because it will prevent the annual flood damage to their property. Residents will no longer need to worry about placing sandbags throughout their community and on their property each summer. The residents will be able to feel safe in their homes and not be affected by the financial burden associated with annual flood damage.
