Munsel Lake (Lane)
Reachcode: 17100206000581 | Area: 104.7 acres | Shoreline: 3.2 mi | View on Interactive Map
(From Atlas of Oregon Lakes, Johnson et al. 1985). Munsel Lake is the last in a chain of four lakes on the central Oregon coast that lies on the North Florence dunal aquifer. The aquifer is an important source of domestic water supply for the Florence area. Unlike the other three lakes in the chain - Collard Lake, Clear Lake and Ackerly Lake - Munsel Lake is also important as a recreational area and is used for fishing, swimming and boating.
The geologic origin of all these lakes is similar and is detailed in the earlier report on Clear Lake in this volume. In brief, the dunal aquifer, formed by the accumulation of aeolian (wind-blown) sand, lies on a down-warped marine terrace extending from Coos Bay to Heceta Head. The dune sheet is broad and relatively flat and is composed of successive layers of sand that were built up as deflation plains behind eastward migrating sand dunes. Munsel Lake and the others in this string lie along the eastern margin of this dune sheet, a result of the migration of sand eastward toward the impermeable bedrock of the Coast Range. As the migrating dunes approach the hills the wind loses its ability to transport sand and the largest portion of the sand remains to the west, thus leaving a depression or series of troughs along the base of the hills. The north-south ridge extending from Herman Peak to Siuslaw Bay is thus coincident with the series of lakes. Munsel, Clear, and Collard Lakes are therefore a result of marginal ponding by dune masses, a mode of formation typical of many other lakes on the Oregon coast (Cooper 1958).
The sands of the North Florence dunal aquifer are very permeable, as indicated by the lack of any substantial amount of surface drainage. No streams originate on the sands, in spite of annual precipitation of more than 60 inches. Sutton Creek and the Siuslaw River, the two major streams that cross the area, derive most of their flow from the foothills of the Coast Range to the east; the aquifer also discharges water directly into them. The main internal surface drainge originates at Collard Lake and flows through a small stream to Clear Lake. Clear Lake water flows by a surface stream to Ackerly Lake, to Munsel Lake and on out Munsel Creek. This creek leaves the northwest corner of the lake and flows in a southerly direction, discharging into Siuslaw Bay at Florence. Seasonally, surface streams do not flow out of Clear or Munsel Lakes; but within a mile, Munsel Creek begins to flow as a result of influent groundwater and this flow increases steadily culminating in an average annual discharge of about 3000 acre-feet. Munsel Creek exhibits an unusual seasonal flow regime because of the nature of its drainage basin. Fall precipitation is held back because of the high infiltration rates and high storage capacity in the dunal areas and because of ponding in the upper lakes, so that the surface stream does not attain high flows until late November. During winter and spring discharge is greater and more uniform than in other streams of comparable size.
Munsel Lake is deeper than most of the coastal lakes, with a maximum depth of 71 feet. The north, east, and south slopes of the lake basin abut the foothills of the Coast Range and are quite steep both above and below the water surface. The west side is flatter because it is influenced by sand dune development, and it has a gently sloping bottom covered with sand. Patches of emergent macrophytes such as water shield, bullrush, and waterlily cover the extensive shoal area along the west shore. Fallen conifers litter the shoreline on the other three sides. There is a small, marshy area adjacent to the northeast shoreline which has been artificially filled to some extent. The deeper parts of the lake are covered with organically enriched sediments.
Munsel Lake is important locally for recreational use and as a supply of water for domestic use. The City of Florence also maintains a small water right for emergency use. The shoreline of the lake is almost entirely in private ownership, and about 40 percent of it is developed (Bryant et al 1979). Heaviest development has been on the west side of the lake where there are several summer homes and permanent dwellings. A county boat ramp is located at the southeast corner of the lake and can be used to launch small, hand-carried craft. Nearby is a private resort with rental boats and other supplies. Primary users of the lake are early season trout anglers. There is a good population of native cutthroat trout and the lake is stocked regularly with rainbow trout by the Oregon Department of Fish and Wildlife; however, because the tributary streams have sandy bottoms, trout are unable to spawn. Good sized largemouth bass and several other warm water species are also taken by anglers. Although fishing is generally good, the level of use is not high. Dense brush restricts the amount of shoreline available for bank fishing to a stretch of about 200 yards near the boat ramp.
The water quality in Munsel Lake is quite good. Characteristic of coastal lakes in Oregon, the concentrations of major ions, the alkalinity, and the conductivity are quite low. Total phosphorus and chlorophyl concentrations, water transparency, and the species and density of phytoplankton present all suggest that the lake ismesotrophic, but very close to oligotrophic. There is a tendency for oxygen depletion in the deeper water and Kavanaugh (1973) and Bryant et al (1979) reported an anoxic, oxygen-depleted hypolimnion in September. The explanation for this may lie, in part, with the morphometry of the lake basin and the locations of inflow and outflow; water may have some tendency to bypass the deep part of the basin on the east side. Also, it is a relatively deep lake in comparison with surface area, and it is somewhat sheltered from the wind; these factors would limit the effects of wind mixing. A third reason for the oxygen depletion may be related to the fact that water in Munsel Lake is somewhat warmer than in other nearby lakes, because it is the last in a hydrologic series of lakes.
As noted, there are a few macrophytes scattered around the littoral area of Munsel Lake, but no extensive beds have developed as they have in many other coastal lakes. Skeesick (1965) reported sparse stands of Brasenia, Potamogeton, Nuphar, and Scirpus. A plankton sample collected on 6/12/73 (Kavanaugh 1973) included Dinobryon sertularia, Peridinium cinctum, Asterionella formosa, Tabellaria fenestrata, Tabellaria flocculosa, and Melosira in the phytoplankton, with Keratella cochlearis and Kellicottia longispina in the zooplankton. The apparent difference in phytoplankton species between the 1973 sample (net plankton) and the 1981/1982 samples (nannoplankton) reported here is probably not as large as it appears due to the use of different sampling techniques. Most of the dominant nannoplankton species (Cyclotella stelligera, Rhodomonas minnta, and others) are small enough to escape through a net. Also, Dinobryon sertularia, Asterionella formosa, and Peridinium cinctum were found in some of the nannoplankton samples, but at very low densities.
The list of plants below includes results of aquatic plant surveys conducted by the Center for Lakes and Reservoirs as well as aquatic invasive plant species detections that have been reported to iMap Invasives: an online, GIS-based invasive species reporting and querying tool.
Plants listed in the table below are categorized as native to Oregon, on the Oregon Department of Agriculture’s (ODA’s) Noxious Weed List, on the Federal Noxious Weed List, or non-native but not listed as noxious. Federal Noxious Weed List plants are plants determined by USDA to be serious threats to U.S. agriculture, irrigation, navigation, public health or the environment (7 C.F.R. 360.200). The ODA Noxious Weed categories are:
ODA Class A - weeds either unknown or with small enough infestations to make eradication or containment possible; targeted for eradication or intensive control.
ODA Class B - regionally abundant weeds (may have limited distribution in some counties); targeted for local/regional control on case-by-case basis.
|-||Utricularia vulgaris (common bladderwort)||Native||CLR|
|-||Najas flexilis (common naiad)||Native||CLR|
|-||Potamogeton robbinsii (fern leaf pondweed)||Native||CLR|
|-||Nymphaea odorata (fragrant waterlily)||Non-native||CLR|
|-||Potamogeton gramineus (grass-leaved pondweed)||Native||CLR|
|-||Potamogeton amplifolius (large-leaf pondweed)||Native||CLR|
|-||Nitella flexillis (Nitella)||Native||CLR|
|-||Potamogeton epihydrus (ribbonleaf pondweed)||Native||CLR|
|-||Potamogeton richardsonii (Richardson's pondweed)||Native||CLR|
|-||Carex sp. (sedge)||Native||CLR|
|-||Schoenoplectus subterminalis (water clubrush)||Native||CLR|
|-||Brasenia schreberi (watershield)||Native||CLR|
|Aug. 15, 2003||Nymphaea odorata (fragrant waterlily)||Non-native||IMAP|