HAB has downloaded and processed the alum application data from the barge’s guidance and dose control computer system. The dose rate coverage map shows each individual application path and the associated dose rate that were recorded over the course of the Rice Marsh Lake application. We are extremely pleased with the precise application and uniform…
Today (9/26/18) the Rice Marsh Lake alum application project was completed on schedule! As planned, the exact dose of over 33,000 gallons of alum was applied in a precise, uniform, and most importantly, safe manner. There is no greater measure of success than safety and Rice Marsh Lake marks HAB’s 76th project without a safety…
Today (9/26/18) marked the second day of application and the lake was busy with visitors and observers. An interested group took advantage of the beautiful Minnesota fall weather and gathered to participate in the Rice Marsh Lake Alum Demonstration Day. Participants were able to learn more about the plan and goals for the Rice Marsh…
The Project Begins!
HAB had a full and productive day of application at Rice Marsh Lake today and applied over 25,000 gallons of alum to a 50 acre zone in the center of the lake. We also spent time conducting our daily environmental testing of the lake water. Alum is widely used in lakes and the drinking/wastewater treatment…
Preparing for Application
On Monday, HAB spent the first day of the Rice Marsh Lake project preparing equipment for the application. This included assembly of the barge’s application boom, programming the barge’s computerized dosing system, launching the barge into the lake, setting up on-shore storage tanks and confirming the delivery plan for the alum. A small restricted work…
How Does an Alum Application Affect Fish and Plants?
Aluminum is considered a non-essential metal because fish and other aquatic life do not need it to function. There is a large body of scientific literature documenting the safe use of alum in lake environment conditions, which has allowed the North American
Lake Management Society to fully endorse its use (NALMS, 2017).
Is Alum Safe?
Alum has been repeatedly shown to be safe for humans. Alum is a common
food additive and has also been used for decades to clean our drinking
water before consumption. HAB uses the exact same drinking water certified
alum when preforming a lake improvement application.
What is Alum and How Does it Work?
Alum (aluminum sulfate) is a nontoxic liquid that
is commonly used in water treatment plants to
clarify drinking water. It’s use in lakes began in
the early 1970’s and is used to reduce the amount
of phosphorus in the water. Lower amounts of phosphorus lead to lower amounts of algae and the symptoms associated with poor water quality. Alum is most often used to control phosphorus release from the lake bottom sediments (internal loading). Research has shown that even when external sources of phosphorus from the surrounding watershed are lowered, the internal cycling can continue to support signi cant nuisance algal blooms.
Where Does All of This Phosphorus Come From?
Phosphorus enters lakes from two sources. Phosphorus entering the lake from outside sources are called external sources. These sources originate in the watershed and are either directly rinsed into the lake or flow to a stream that enters the lake. Common external sources include lawn fertilizers, septic systems, agricultural practices, stormwater, soil erosion and geese: anything that causes phosphorus to enter the lake from the watershed.
Once the external source of phosphorus enters the lake, it is deposited in the lakebed and is recycled back into the water column. This is the second source of phosphorus and it originates from within the lake itself. This is called an internal source and these inputs are most common during the summer
and winter when water oxygen concentrations are low or zero near the bottom. This condition causes changes in the chemistry of the lakebed that lead to the phosphorus leaching out of the sediment and into the water.