Little Hay Creek stream restoration

Background

Little Hay Creek originates from springs and bog seepage in St. Croix State Park and flows west 1.4 miles before entering Hay Creek, just west of the park boundary. A 1919 survey of streams in Pine County classified Little Hay Creek as a coolwater trout stream with numerous fingerling brook trout present. There are no records of management or habitat improvement on Little Hay Creek until 1967 when a stream survey was completed. At that time the stream was devoid of trout, with numerous beaver dams. Intensive beaver control and dam removal were done from 1968-1980; a 1985 stream survey found Little Hay Creek to be one of the top brook trout streams in Pine County. However, beaver control and dam removal were discontinued in the 1980Â?s, and by 1995 beaver had once again taken over the stream. In ten years the average stream width had increased by 22 feet, substrates had become predominantly silt, muck and detritus, and water temperatures and dissolved oxygen levels were unsuitable for brook trout. No trout were sampled by electrofishing.

In 1998, the Hinckley Area Fisheries Office initiated an ongoing project on Little Hay Creek, in cooperation with St. Croix State Park . The goal was to restore and maintain a naturally reproducing brook trout population in the entire stream. Elevated stream temperatures caused by beaver dams and impounded water were the primary limiting factors that had kept the natural brook trout population at a minimum.

Pre-project data

During April 1998 Phase I of the project was to record the number of beaver dams, take flow and channel measurements, assess the immediate riparian surroundings, and conduct a fish population assessment. Fish sampling by backpack electrofishing discovered 10 adult brook trout along the entire 1.4 mile reach.

Habitat improvement and immediate results

Phase II soon followed from May 1998 through the end of 1998. Hand removal of 39 beaver dams was achieved by mid-May in the 1.4 mile stream reach. Beaver removal by trapping caught two adults, which were the only active beaver on the stream. Continued beaver control would follow but no new beaver were observed in Little Hay Creek until one was trapped in December 1998. Once all dams were removed, the stream depth and channel width was lowered considerably while flow velocities increased. Constant scouring of detritus materials within the original stream bed had revealed historical sand/gravel bottom substrates and cleaned up critical gravel/rubble riffle areas. The mucky exposed stream banks and flats were seeded with an annual rye grass to stimulate quick growth of grass and provide bank stabilization.

For one week in early July, many log jams and excessive woody debris blocking the stream channel were removed and placed along stream banks that needed mending from erosion. By this time efforts were evidently paying off. Detritus was decreasing while sand and gravel areas were increasing, although it was a slow and gradual process. A dry summer created low base flows and storm flushing events were not occurring. On September 9-10, 1998, backpack electrofishing along the entire 1.4 mile reach found 71 brook trout of which 30 were young-of-year trout. Successful spawning had occurred nearby and more fish were using the stream. Temperature recorders were set in the stream during the warm summers months to show maximum and minimum temperature variations.

The last objective of the year was to trim back the dense growth of alder brush from the stream banks. This was done in late November and early December when the ground was partially frozen. While shading the stream channel to keep water temperatures down is important, Little Hay Creek is short enough with enough base flow from springs to run its whole course and still have very cool water before entering Hay Creek. Pulling the alder brush from the banks would allow more sunlight to penetrate the area and stimulate new growth of dense grasses and sedges. These grasses overhang the stream bank and create habitat, cover, and shade.

Ongoing work and monitoring

Around 500 hours of labor were spent on Phases I and II for field work and planning, at a cost of less than $10,000. Maintenance work since 1998 has consisted of periodic beaver trapping and dam removal at an average cost of less than $500 per year. Stream population assessments in 1999, 2000, 2002, and 2004 have monitored the brook trout population. The catch rate of adult brook trout increased from 3.2/hr in 1998 (before work was done) to 8.5 in September 1998 after work was completed. Since then the adult catch rate has varied from 6.0/hr in 1999 to 17.9/hr in 2002; the catch rate in 2004 was 9.5/hr. The catch rate for young of year brook trout was highest in 2000, with 79.4/hr; in 2004 it was 57.0/hr, compared with no young-of-year brook trout prior to habitat improvement.