Emigrant Lake (Jackson)

Reachcode: 17100308006269 | Area: 780.7 acres | Shoreline: 13.2 mi | View on Interactive Map

(From Atlas of Oregon Lakes, Johnson et al. 1985).  Emigrant Lake is a reservoir located in the broad valley of Emigrant Creek to the east of Ashland, and was formed in 1926 when the creek was dammed to store water for irrigation and to provide protection from floods. The name is in honor of nineteenth century emigrants who crossed the Cascade Range over the southern route and came down this stream into the Rogue River Valley. Today, the lake is easily observed from Interstate Highway 5 and is generally the first Oregon lake seen by travelers as they enter the state from the south.

In 1960 the dam was raised to a height of 198 feet and the lake enlarged. It now covers a surface area of 878 acres and holds over 40,000 acre feet of water at full pool. Built by the U. S. Bureau of Reclamation, it is operated as a part of the Talent Irrigation Division, a project which includes Howard Prairie Lake, Keene Creek Dam, Agate Lake, and the Green Springs power plant. Howard Prairie Lake and Keene Creek are in the Klamath Basin, and whenever there is surplus water available on the Klamath side of the Cascade divide, it is diverted into Emigrant Lake via Keene Creek diversion dam, the Cascade Divide Tunnel, and the Ashland Lateral Canal. Natural inflow to Emigrant Lake is from an area of 64.3 square miles; primary streams are Hill Creek and Emigrant Creek. Land in the drainage basin is mostly in private ownership, interspersed with federal lands administered by the Bureau of Land Management. The shoreline is entirely under county management as the Emigrant Lake Recreation Area. Outflow is into Emigrant Creek, tributary of Bear Creek, and into the East Lateral Canal. Primary purpose of the waters released from Emigrant Lake is for irrigation downstream in the Talent-Medford area, and as a result the lake fluctuates widely in surface area throughout the year.

Emigrant Lake is also a popular recreation spot. In spring and summer there is heavy use for fishing, boating, and swimming. However, as the seasonal drawdown for irrigation progresses in late summer boat launching ramps and floating docks are left stranded and the remaining water is surrounded by a broad belt of soft, stinking mud. The lake is then unused for recreation until spring. The water level does not necessarily fall continuously, because Klamath Basin water is periodically diverted into Emigrant Creek. As long as water levels are up, there is good angling for largemouth bass and crappie, and some rainbow trout are caught. Camping in the Emigrant Lake Recreation Area extends through the whole summer, even when the lake itself is unusable. There is also a large picnic area, a swimming beach, playground facilities, and a boat ramp on the shoreline.

Emigrant Lake exhibits a distinctive branching shape, with two major arms extending up the valleys of Hill Creek and Emigrant Creek. Extensive shallow areas are found in the upper portions of these arms, although three dikes along the northwest edge of the lake reduce the amount of shallow water somewhat. Bottom material consists primarily of clay and fine sediment, which is easily resuspended as the level of the lake varies, and on occasion it reduces water transparency. When there is no direct influence from suspended sediment, transparency is moderate (Secchi disk depth = 8.0 feet; 2.4 meters on 7/12/82). Concentrations of major ions, alkalinity, and conductivity are above average for lakes and reservoirs in the Cascades. Calcium and magnesium, in particular, are well above average, possibly as a result of weathering of clays and sedimentary rock in the basin.

The reservoir has experienced a history of problems with algal blooms. Because it is mud-bottomed and is shallow for much of the year, with consequent rapid warming of the water, there is almost a continuous bloom of blue-green algae during the summer. Aphanizomenon flos-aquae has been commonly observed, approximating a "green paint" condition over much of the reservoir. It is highly unlikely that the frequent blooms are stimulated by direct human agency. Sewage and washing water from campgrounds, picnic areas, and trailer parking areas are either pumped and removed from the drainage or treated in a sewage treatment plant, the effluent from which is sprayed on dry hillsides. The heavy growths of blue-green algae, mostly Aphanizomenon, have discouraged swimming at times and have been the source of complaints about bad odors.

According to McHugh (1979), this reservoir would be a good place to try iron precipitation by the permanganate method, followed by phosphate and manganese precipitation by alum. The objective of iron-alum treatment would be to shift the plankton from blue-green algae to diatoms or green algae, which are less disagreeable, do not produce odors as offensive as those of blue-greens, and do not form the dense floating surface scums that blue-green algae do. Emigrant Lake will probably always have abundant summer algal plankton, as mud-bottomed reservoirs provide nutrients directly from the bottom sediments. Also, the surplus water diverted into Emigrant Lake from the Klamath Basin is well-enriched. Based upon the history of problems with algal blooms, as well as other indices, Emigrant Lake is classified as eutrophic.


The list below includes results of zebra and quagga mussels surveys conducted by the Center for Lakes and Reservoirs and other agencies. The results "non-detect" and "results pending" indicate that surveys for zebra and quagga mussels were conducted, but none were detected or results are pending. For more details on zebra and quagga mussel monitoring, please visit the Online Mussel Monitoring Map.

Date Status/Species Source
Aug. 22, 2013 non detect Portland State University
July 12, 2013 non detect Portland State University
Aug. 27, 2010 non detect Oregon Dept of Fish and Wildlife
July 26, 2010 non detect Portland State University

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.

Download the complete dataset as a CSV

Date Species Status Source
Aug. 5, 2011 Fontinalis sp. (aquatic moss, fontinalis moss) Native CLR
Aug. 5, 2011 Potamogeton crispus (curly leaf pondweed) Non-native CLR
Aug. 5, 2011 Lemna sp. (duckweed) Native CLR
Aug. 5, 2011 Mentha sp. (mint) Native CLR
Aug. 5, 2011 Limosella aquatica (mudwort) Native CLR
Aug. 5, 2011 Chara sp. (muskwort) Native CLR
Aug. 5, 2011 Potamogeton sp. (pondweed) Native CLR
Aug. 5, 2011 Potamogeton epihydrus (ribbonleaf pondweed) Native CLR
Aug. 5, 2011 Potamogeton diversifolius (snailseed pondweed, diverse leaf pondweed) Native CLR
Aug. 5, 2011 Eleocharis sp. (spikerush) Native CLR
Aug. 5, 2011 Nitella sp. (stonewort) Native CLR
Aug. 5, 2011 Ranunculus aquatilis (water-buttercup) Native CLR
Aug. 5, 2011 Marsilea sp. (water clover) Native CLR
Aug. 5, 2011 Ludwigia palustris (water-purslane) Native CLR
Aug. 5, 2011 Persicaria amphibia (water smartweed) Native CLR
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