Projects

Fawn River Restoration & Conservation Charitable Trust is working to restore Fawn River – one of Indiana’s finest rivers – after an event that inundated a five mile section of the stream with over 100,000 cubic yards of organic silt and fine sand, burying the previously pristine gravel and cobble bottom.

Excess sediment is the nation’s leading cause of water quality and aquatic habitat impairment. The diversity, health and quantity of river life is directly linked to both the quality and amount of clean gravel and cobble bottom.

The Fawn River Restoration & Conservation Charitable Trust is diligently working to improve the water quality and enhance the aquatic habitat of this once pristine river.

Streamside Environmental, was contracted by the Trust to implement their Sand Wand™ System on Fawn River. This proprietary technology selectively removes the non-native silts & fine sand material while leaving the native cobble and gravel in place.

A little background

Coaster brook trout were once common throughout Lake Superior basin tributaries and near shore waters, but the populations were wiped out due to over-fishing and habitat degradation. The Salmon Trout River, in Marquette, Mich., hosts the last known remnant breeding population of coasters in the area. Michigan Tech has been conducting long-term research on the status and ecology of this population since 2000. Based on annual assessments of coasters using stationary fish-counting weirs and visual counts of fish at spawning sites, the population appears to consist of only a few hundred adults that ascend the river each fall to spawn. Over the last decade, the Salmon Trout River has become degraded by land use and roads in the watershed causing erosion. Sand now covers the small section of stream-bottom cobbles where the majority of coasters once spawned, making the existing small population even more at risk of dying out. As sand continues to cover the cobbles and gravels where the coasters spawn, it also changes ecosystem dynamics; Michigan Tech has been examining these effects as the sands accumulate in the river so they can also study the beneficial effects of removing the sands.

The project

In an attempt to save the main spawning site, a Sediment Collector was installed to collect sediments and prevent bedload from moving downstream. Although the Collector was able to prevent sediment from moving downstream, a Sand Wand restoration was needed to remove the sediment build-up, that existed prior to the Collector installation, which still posed a big problem.  Once the sand was cleared that covered the spawning site, the Collector was able to keep the site clean on its own, allowing coaster brook trout populations a better chance of recovery.

Irish Cove Brook is located on the southeastern side of the Bras d’Or Lake, Cape Breton NS. The lower reaches of the stream are downstream of the #4 Trunk Highway, flowing through an old limestone pit that was reclaimed several years ago; the stream was not restored. The total instream length of the stream between the #4 Highway crossing (454849.7N 604022.1W) and Bras d’Or Lake outlet (454917.8N 604034.8W) is 1040m with a design width of 6.5m, for a total riverine habitat area of approximately 6760sqm

The project

The Sand Wand removed the sand and silt from the substrate. Sand in particular degrades salmonid habitats and is a long term impact that in some heavy cobble or boulder streams will never naturally be removed from Nova Scotia streams. The sand infills the interstitial spaces eliminating the collection of riparian organics that are the major source primary productivity for the stream, greatly reduces insect habitat, impacts or eliminates successful spawning, can eliminate cover habitat for all age classes, including over wintering habitat and can severely damage the pool/ riffle /thalweg development resulting in shallow over widened streams with long runs that restrict migration. The Sand Wand removed the sand and silt down to a depth of 30 cm to 40 cm.

Core samples were taken by working a steel pipe into the substrate at least 25cm and removing the contents by hand. These samples showed the before, with sand and silt, and the after of cleaned gravel. It is clear to see that the intestinal spaces have been cleared and the substrate un-grouted making it 5 to 10 times more mobile and able to be shaped by the stream flows into a more productive pool/ riffle/thalweg stream structure.

In conclusion

The Sand Wand technique removed the sand and silt down to 40cm un-grouting the substrate and allowing the Brook to re-establish a natural pool riffle pattern with excellent quality pools and thalweg. This was achieved without causing new bank erosion or disruption. Every measure of habitat quality was improved.

The Sand Wand has been accepted by DFO Maritimes as a low impact activity and is covered under the NSSA’s NSE blanket watercourse alteration permit for habitat restoration.