[Excerpt from the Red River Basin Board's Flood Damage Reduction Team's Inventory Report- December 2000]

Geographic Setting

The Red River Basin (RRB) is an international, multi-jurisdictional area, approximately 45,000 square miles (28 million acres of land and water) in size, and includes the Devil's Lake Basin (3,180 square miles) (Figure 1) (Krenz and Leitch, 1993).  The Assiniboine River joins the Red River in downtown Winnipeg. Nearly 40,000 square miles of the RRB (103,600 square kilometers) are in the United States; the remaining 5,000 square miles (13,000 square kilometers) are in Canada (Krenz and Leitch 1993). Only 1 percent of the RRB is located in the extreme northeast corner of South Dakota (Krenz and Leitch 1993).

Figure 1:  The Red River Basin

Source: International Joint Commission (IJC) website (www.ijc.org); original source: Environmental and Energy Research Center (EERC),      University of North Dakota.

The RRB consists of twenty-five major sub-RRBs (Figure 2). Four of the sub-RRBs are inter-jurisdictional RRBs, including Pembina (shared by North Dakota and Manitoba), Roseau (shared by Minnesota and Manitoba), Wild Rice (shared by North Dakota and South Dakota), and Bois de Sioux (shared by North Dakota and South Dakota). Seven sub-RRBs, including Devils Lake, Park, Forest, Turtle, Goose, Elm, and Sheyenne, are located entirely in North Dakota. Nine sub-RRBs are located entirely in Minnesota side including Two Rivers, Tamarac, Middle Snake, Red Lake, Sandhill, Wild Rice-Marsh, Buffalo, Otter Tail, and Mustinka-Rabbit. Five sub-RRBs, including La Salle, Morris, Riviere Aux Marais/Plum, and Seine, and Rat, are situated entirely in Manitoba.

  Figure 2. Sub-watersheds of the RRB.

Source: Krenz and Leitch, A River Runs North, 1993. Original source: Souris-Red-Rainy River Basin's Commission.

The unique topography of the RRB contributes to the flooding problem frequently experienced by the RRB's residents. The 'valley' portion of the RRB has a slope of 1-2 feet per mile and has been described as 'a huge dinner plate tilting very slightly to the north' (The International Coalition 1989). At the RRB's margins, the sub-watersheds draining into the Red River main stem have an elevation drop of up to 950 feet in 80-100 miles. When stream banks are full to capacity, excess surface water spreads across the adjoining land surface (Krenz and Leitch 1993). The RRB does not experience spring thaw uniformly. Because the Red River flows north, the upstream (southern) end of the RRB may be melting, while the downstream (northern) end of the RRB may still be frozen. The downstream reaches of the Red River may contain ice jams and/or Lake Winnipeg, which the Red River discharges into, may still be frozen; either of these situations can cause localized flooding upstream of the 'ice dam' and/or slow down the retreat of the floodwaters.