Agate Reservoir (Jackson)

Reachcode: 17100307007004 | Area: 204.6 acres | Shoreline: 3.3 mi | View on Interactive Map

(From Atlas of Oregon Lakes, Johnson et al. 1985). Agate Lake is an irrigation reservoir built by the Bureau of Reclamation in 1966 and managed as a component of the Talent Division of the Rogue River Basin Project, a multipurpose water resource development with emphasis on irrigation. The reservoir was formed by a 77-foot high earthfill, rock-faced dam which impounds the waters of Dry Creek. Inflow to Agate Lake also comes via a canal from Yankee Reservoir. Outflow is into Dry Creek and ultimately into irrigation canals for use downstream. The Medford Irrigation District Canal passes through the Agate Lake drainage basin, carrying water from Fish Lake to the Medford area. Agate Lake is named for the nearby Agate Desert, famous for its abundance of minerals and for its beautiful spring display of wildflowers.

The drainage basin of Agate Lake is mostly private land with some small parcels of Natural Resource Lands administered by the Bureau of Land Management. Agate Lake Recreation Area, a county park, surrounds the lake, so the shoreline is entirely under public management. Recreational use of the lake is primarily by fishermen and the water is fished heavily, despite a ban on motorboats. Small electric motors are permitted. Fishing is best in the spring; bluegills are abundant and crappies and largemouth bass are also present. 

Concentrations of major ions in the water are above average for reservoirs in Oregon, but similar to others in the Rogue River Valley. Above average concentrations of calcium and magnesium indicate the influence of leaching from the soils by irrigation in the drainage basin. Water quality data indicate that Agate Lake is one of the more eutrophic lakes in Oregon. Total phosphorus and chlorophyl concentrations are high and water transparency is limited. Blooms of phytoplankton occur during the summer months and Anabaena spiroides, a blue-green algae found in enriched waters, was the dominant species on the sample date of 7/14/82. Other associated indicators of eutrophic conditions are the fact that oxygen is sometimes depleted in the deeper water, biological productivity is high, and the lake is overpopulated with rough fish. 

Printable Lake Map
No mussel data available.

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.

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Date Species Status Source
Aug. 26, 2012 Potamogeton nodosus (longleaf pondweed) Native CLR
Aug. 26, 2012 Chara sp. (muskwort) Native CLR
Aug. 26, 2012 Marsilea vestita (pepperwort, clover-fern) Native CLR
Aug. 26, 2012 Potamogeton pusillus (slender pondweed) Native CLR
Aug. 26, 2012 Najas gracillima (slender waternymph) Non-native CLR
Aug. 26, 2012 Eleocharis sp. (spikerush) Native CLR
Aug. 26, 2012 Nitella sp. (stonewort) Native CLR
Aug. 26, 2012 Persicaria amphibia (water smartweed) Native CLR