Floyd Lake, a 1,178 acre, general development lake with heavily developed shoreline located north of the City of Detroit Lakes. The lake is divided into two distinct basins, known locally as Big Floyd and North Floyd. The lakes are heavily used for game fishing, boating, and other summer and winter recreational activities. The larger of the two basins, Big Floyd is 862 acres in size, reaches a maximum depth of 25 feet, and has approximately 5.5 miles of shoreline. The littoral area (<15 ft) of the lake accounts for nearly 70% of the lake area and emergent aquatic plants are common. “North” Floyd is smaller with 316 acres of surface area, 2.2 miles of shoreline, and has a maximum depth of 34 feet. North Floyd littoral area (<15 ft) coverage is approximately 60%. There is one MN DNR owned public access located on the southeast side of Big Floyd. North Floyd Lake does not have a public access.
The Floyd Lake drainage area is 4,916 acres, extending to the west and north. Much of the land cover, excluding open water, in the drainage area is forested (40%) and grassland (23%). Cultivated land crops account for 20% of land cover and are primarily located in the upstream Campbell Creek drainage area. Developed land (11%) in the area consists of shoreline residential housing and a few commercial storage businesses.
At 882 acres in size, Big Floyd is significantly larger than the connected North Floyd. Big Floyd has a maximum depth of 26 feet, which is also happens to be the PRWD monitoring location. There are no significant river or stream inputs to the lake. Most the surface water inputs to the lake, is from stormwater runoff. The shoreline is highly developed with predominantly single family homes. There is one public access that is located on the south end of the lake. Most of the time, Big Floyd’s water is clear, with moderate phosphorus and algae concentrations, good game fish populations, and will moderate aquatic plant growth. Big Floyd exhibits above average water quality in comparison with other District Lakes and is considered mesotrophic with annual averages of 12.5 feet of water clarity and 18 ppb in-lake phosphorus concentrations.
The North arm of Floyd Lake is 281 acres in size and reaches 32 feet in depth. The shoreline is less developed that Big Floyd, but in recent years, previously natural shoreline areas on the north side of the lake are being developed into single family homes.
The major water source into North Floyd is Becker County Drainage Ditch 12/Campbell Creek along with two minor inlets located on the west side of North Floyd and on the southwest side of Big Floyd. Campbell Creek is an intermittent, high gradient stream and is the major nutrient source to North Floyd Lake. Sections of Campbell Creek were ditched and straightened in the early 1900s for agricultural benefit and included partially drawing down Campbell Lake and draining surrounding wetland areas. Becker County Ditch 11-12 discharges into Campbell Creek, a natural channel which drops almost 80 feet in 2 miles before reaching North Floyd. Through the lower reach, Campbell Creek passes through eroding and highly erodible soils, and carries a heavy sediment load to North Floyd. It appears that most of the time Big Floyd also contributes some flow to North Floyd, although it is thought the source of this water is mainly from groundwater. Other minor water sources include overland flows and groundwater seeps and springs. The outflow is located on the east side of North Floyd and connects to Little Floyd through Becker CSAH21 road culvert.
Big Floyd - Water quality in the 2017 season was lower than average with a mean water clarity of 9 feet, 25% lower than the average for the last 10 years. Big Floyd was not scheduled to be sampled for chemistry in 2017, so those values are unavailable. That schedule will be adjusted in future years to ensure that chemistry samples are taken on Big Floyd and North Floyd Lake during the same year, allowing for better comparison.
Low spring rains and minimal snowmelt resulted in very high water clarity readings. This trend ended abruptly with a very large mid-July storm event. During the event, high winds caused trees with shallow roots along the shoreline to be lifted, exposing highly organic and nutrient rich soils which eroded into the lake. Water clarity dropped by nearly 2 feet following the storm event.
In mid-August the weakly stratified lake mixed, causing nutrients that were confined to the bottom layers to be brought to warmer sunniersurface water. The warm late-August air temperatures and sunlight caused large algal blooms and caused yet another drop in water clarity.
North Floyd - In 2017, two factors combined to reduced streamflow and, in turn, decreased normal nutrient and sediment loads. Lower that average rainfall from March-July minimized stormwater runoff. In additional to below average rainfall, a beaver dam blockage further reduced flow from Campbell Lake. July and August streamflow were so low that, at times, measuring streamflow was not possible. Higher than average August rainfalls restored flow from Campbell Creek and with that, severe late season algal blooms. It is apparent in comparing water clarity to rain events, that North Floyd is very sensitive to increased flows from Campbell Creek.