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Florida Lake Management Society Annual Conference, Naples, Florida, June 4 – 7, 2007

St. Paul Regional Water Services Reservoirs and Watershed Restoration Program

David Schuler St. Paul Regional Water Services St. Paul, Minnesota

The Saint Paul Regional Water Services (SPRWS) provides potable water to the cities of St. Paul, Arden Hills, Falcon Heights, Lauderdale, Little Canada, Maplewood, Mendota, Mendota Heights, Roseville and West St. Paul. The SPRWS treatment facility receives source water from a chain of reservoirs, which includes Pleasant Lake, Sucker Lake and Vadnais Lake. These reservoirs are augmented with water from the Mississippi River and local watersheds.

The SPRWS has been plagued with severe taste and odor problems in the water supplied to the public. Most of these problems can be traced to the degraded water quality of the source water reservoirs brought on by excessive algal growth. In 1984 SPRWS initiated an intensive diagnostic study of the source water reservoir system and contributing watersheds. The results of the study indicated that nutrient enrichment, with phosphorus as a limiting nutrient, had produced abundant algal populations, which in turn produced taste and odor compounds. Identified sources of phosphorus loads into the reservoir system included the Mississippi River, internal loads from lake sediments and local watersheds – primarily Lambert Creek.

Phosphorus loadings from the Mississippi River source and reservoir sediments were addressed by capital projects funded by SPRWS. A Phase I CWP diagnostic study of Lambert Creek was conducted under the sponsorship of the Vadnais Lake Area Water Management Organization (VLAWMO) in 1991. This study revealed that wetlands along the course of Lambert Creek had high sediment phosphorus concentrations and release rates. The problem was further exacerbated by the fact the wetlands had been drained when Lambert Creek became a county drainage ditch in the early 1900’s and the City of White Bear Lake had used the headwaters as a stabilization pond for the municipal wastewater effluents. The subsequent wet/dry cycling of the wetland via climatological conditions provided for periods of

decomposition of detritus followed incorporated into the workplan, which control structures on the outlets.

by flushing to Vadnais Lake. called for “reconstruction” of the

These

findings were

wetlands

via man-made

Management Measures

Lambert Creek Watershed

SOBOTA

SUCKER

RICE L. GRASS L

Project Area

GEM

GOOSE

The primary focus of the work plan is to reduce the mass of phosphorus runoff to Vadnais Lake. Long term statistical analysis has indicated that in order to lower taste and odor episode frequencies

to acceptable levels, total to remain equal to or micrograms per liter in

P values need less than 25 mixed layer

LAMBERT L.

samples from This should

April through September. reduce the frequency of

VADNAIS

chlorophyll

A

concentrations

exceeding

Session 5B – Page 5

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