Mirror Pond (Deschutes)
Reachcode: AOL000080 | Area: 65.9 acres | Shoreline: 4.9 mi | View on Interactive Map
(From Atlas of Oregon Lakes, Johnson et al. 1985) Mirror pond is a controlled section of the Deschutes River located in the developed portion of the city of Bend. It stretches from the Pacific Power and Light Company Dam to Galveston Avenue, a distance of about one mile. Over the years, private homes have been developed along the pond's edge, primarily on the western side of the river. Drake Park fronts most of the pond on the east side of the river, and three smaller parks border portions of the park on the west side. All of these parks provide public access to the pond area. Siltation has curtailed much of the former recreational use of Mirror Pond. In addition to reducing depths, siltation has encouraged excessive growth of macrophytes that further interfere with boating, fishing, and swimming and creates unpleasant odors at times. Vegetative growth is related to the shallow depths, which allow sufficient light on the bottom to encourage macrophyte growth. These problems were investigated by an EPA-funded study under the Clean Lakes Program (Winzler and Kelly; Clark and Joyce 1981). They found that there has been no drastic increase in any water quality parameter related to the location within Bend that could contribute to eutrophication. Biological oxygen demand levels upstream and downstream from Bend do not indicate gross organic pollution, but sufficient levels of nitrogen and phosphorus are available in the Deschutes River upstream from Bend to promote eutrophication. No single source of land use can be blamed for eutrophication or sedimentation problems in the pond. This is due to the fact that the water quality of the pond is essentially that of the Deschutes River which would then reflect any problems from the extensive use of the drainage basin. Likely sources of sediment and pollutants include: natural sediment load, faulty septic systems, agricultural runoff, sediments from failed riverbanks, and turf fertilization. Mirror Pond acts as a settling pond to accept nutrient-enriched sediment from all these sources. Proposed rehabilitation efforts are directed at resolving the primary problem of siltation and the resulting shallow water depths. Some alleviation of the secondary problem of macrophyte growth is expected, but dredging at depths greater than available funds allow would be required to achieve a long-term suppression of plants. Bucket and hydraulic dredging methods were two alternatives examined. Based on lower cost, fewer turbidity problems, and lesser impacts on park and residential areas, hydraulic dredging was selected. Sources of funding are being sought with dredging expected to occur in 1984 depending on sufficient funds and proper conditions to lessen impacts on the fish and wildlife. From a water quality standpoint, Mirror Pond is essentially an extension of the Deschutes River and reflects the quality of the river at that point. Most of the flow through the pond follows the old river channel and has been further confined by the siltation and macrophyte growth. The pond receives water draining from Wickiup, Crescent, and Paulina Lakes. Average water quality data collected by DEQ from 1979-1983 is presented for a site on the Deschutes River approximately one mile downstream at the Irrigation Division Dam. As shown, ion concentrations are similar, although slightly higher than those found in Wickiup Reservoir and reflect a mix of water draining from the three tributary lake basins. Phosphorus levels are fairly high but are similar to those levels found in lakes from this region of the Cascades. Chlorophyl values are moderate although they have ranged from 0.9 to 21 ug/1. As the pond is shallow and dominated by river flow, it does not stratify. Generally, the pond can be classified as mesotrophic.