Little Limestone Lake

Protecting Manitoba’s Colour-changing Lake

Little Limestone Lake, near the northwest tip of Lake Winnipeg, is Earth's largest marl lake. Marl is created when calcite, a constituent of limestone, is chemically precipitated from warm water. As the temperature rises, the quantity of marl increases, which changes the colour of the lake. It is common for the lake to transform from a brilliant turquoise in the morning, to a robin's egg blue by mid-afternoon.

CPAWS has been working for years to ensure a sufficient area around the lake is protected so the water body's ecology remains intact and the needs of local communities are met.

We were delighted when the province designated Little Limestone Lake a park reserve in July 2007. The park reserve provides interim protection for the lake and 100 metres of surrounding shoreline. This measure safeguards the area from developments during a consultation process designed to determine the future for Little Limestone Lake.

The present boundaries of the park reserve are inadequate to ensure Little Limestone’s water quality. If polluted waters enter from outside of the protected boundary it may cause irreparable damage to Little Limestone’s delicate eco-system. Protecting its groundwater sources is required to ensure the lake’s well-being.

CPAWS is working with all involved to make certain a large enough area around the lake is permanently protected to maintain the lake’s health as well as traditional activities and sustainable tourism opportunities for the area’s residents.

CPAWS has commissioned Dr. Derek Ford, the world’s leading marl lake specialist, to undertake a study that will delineate Little Limestone Lake’s watershed. The results will be distributed widely for the purpose of informing decision-makers and influential individuals on the most ecologically appropriate boundaries. A public-friendly document will also be produced and circulated to local residents and general public.

Protecting Little Limestone Lake and surrounding lands will be a giant step forward in creating a healthy future for local communities, Manitobans, and the Earth.

Former CPAWS President Roger Turenne, Manitoba Conservation Minister Stan Struthers, and CPAWS Manitoba Executive Director Ron Thiessen on a day tour of Little Limestone Lake.