Today, Holter Dam and Holter Lake are a popular recreational area for boating, fishing, hiking, and camping.
Just below Holter Dam is the Blue Ribbon trout fishing section of the Missouri River.
Five-pound (2.27 kg) rainbow trout are commonly caught here, and trout weighing 10 pounds (4.5 kg) or more have been caught.
Many fish are 18 inches (460 mm) or longer.
Rainbow trout outnumber brown trout here by a 6:1 ratio.
At Holter Lake, rainbow trout weighing 3 pounds (1.4 kg) are commonly caught.
There are also stable, significant populations of burbot and stonecats below the dam.
Until recently, kokanee salmon and yellow perch were also abundant below the dam, but increasing number of walleye and increased water flows have reduced these populations to as little as 4 percent of historic levels.

According to Montana wildlife officials, "Holter Reservoir has historically been one of the most diverse and productive multi-species fisheries in the state."
Rainbow trout, kokanee salmon, walleye, and yellow perch are all found there in abundance.
In 1992, "catch-and-release only" regulations were imposed on brown trout to protect the fragile population numbers of these fish.
Eight years later, state officials imposed a 50-fish limit on the number of yellow perch which may be caught.

Management of the fishery immediately downstream of Holter Dam necessarily involves management of the dam and reservoir.
In autumn 1996, whirling disease was confirmed in the Missouri River below Holter Dam.
Fishing on the 15-mile (24 km) stretch of Missouri River below Holter Dam doubled between 1989 and 1999, according to the Montana Department of Fish, Wildlife and Parks.
These pressures led state wildlife managers to implement in March 2002 limits on the catch of rainbow trout on this part of the Missouri River.
By 2002, fishing levels just below Holter Dam had doubled from their 1993 levels.
This section of the Missouri River was now the most heavily fished body of water in the state.
In 2009 and 2010, a fungal disease killed large numbers of mature brown trout below Holter Dam.

Holter Dam was relicensed by the federal government in 1997.
Until that year, a steering committee composed of state fish and wildlife experts, the Montana Power Company, the United States Bureau of Reclamation, the United States Forest Service, and representatives of agricultural irrigators and sportsmen managed Holter Dam to optimize recreation and to minimize negative impacts on fish and wildlife.
The dam's owners were required to conduct an environmental impact statement as part of their 1997 relicensure, however.
This document led to new guidelines, adopted by PPL, which requires the dam's owner to not only continue to operate Holter Dam as a run-of-the-river dam but also to maintain water levels behind the dam within a certain range.
In January 2011, as part of its management efforts, PPL agreed to donate $1.2 million to fund 41 conservation projects along the Missouri and Madison rivers, which included restoring and increasing riverside vegetation along 4.5 miles (7.2 km) of the Missouri River below Holter Dam and a study of the walleye feeding habits below Holter Dam.

Drought has also affected the dam's operation.
No water was permitted to flow over the dam in 1986 due to drought.
In 1992, water flowed over the dam's crest on only a single day.
In wetter years, water flows over the dam almost continuously.
A severe drought struck the state of Montana beginning in 1999.
By May 2004, the dam was permitting only 3,500 cubic foot (99 m³) to 3,000 cubic foot (85 m³) per second downriver.
These flows were well below the 4,100 cubic foot (120 m³) per second needed to keep the fishery healthy.
The low water flows, coupled with whirling disease, led to a 40 percent drop in big fish (those over 17 inches (430 mm) in length) as well as lower overall numbers of fish immediately below the dam.
A 2005 proposal by the managers of the Helena National Forest to draw down Holter Lake by 2 feet (0.61 m) in August 2005 in order to repair Coulter Campground near the Gates of the Mounta
Today, Holter Dam and Holter Lake are a popular recreational area for boating, fishing, hiking, and camping. Just below Holter Dam is the Blue Ribbon trout fishing section of the Missouri River. Five-pound (2.27 kg) rainbow trout are commonly caught here, and trout weighing 10 pounds (4.5 kg) or more have been caught. Many fish are 18 inches (460 mm) or longer. Rainbow trout outnumber brown trout here by a 6:1 ratio. At Holter Lake, rainbow trout weighing 3 pounds (1.4 kg) are commonly caught. There are also stable, significant populations of burbot and stonecats below the dam. Until recently, kokanee salmon and yellow perch were also abundant below the dam, but increasing number of walleye and increased water flows have reduced these populations to as little as 4 percent of historic levels.
According to Montana wildlife officials, "Holter Reservoir has historically been one of the most diverse and productive multi-species fisheries in the state." Rainbow trout, kokanee salmon, walleye, and yellow perch are all found there in abundance. In 1992, "catch-and-release only" regulations were imposed on brown trout to protect the fragile population numbers of these fish. Eight years later, state officials imposed a 50-fish limit on the number of yellow perch which may be caught.
Management of the fishery immediately downstream of Holter Dam necessarily involves management of the dam and reservoir. In autumn 1996, whirling disease was confirmed in the Missouri River below Holter Dam. Fishing on the 15-mile (24 km) stretch of Missouri River below Holter Dam doubled between 1989 and 1999, according to the Montana Department of Fish, Wildlife and Parks. These pressures led state wildlife managers to implement in March 2002 limits on the catch of rainbow trout on this part of the Missouri River. By 2002, fishing levels just below Holter Dam had doubled from their 1993 levels. This section of the Missouri River was now the most heavily fished body of water in the state. In 2009 and 2010, a fungal disease killed large numbers of mature brown trout below Holter Dam.
Holter Dam was relicensed by the federal government in 1997. Until that year, a steering committee composed of state fish and wildlife experts, the Montana Power Company, the United States Bureau of Reclamation, the United States Forest Service, and representatives of agricultural irrigators and sportsmen managed Holter Dam to optimize recreation and to minimize negative impacts on fish and wildlife. The dam's owners were required to conduct an environmental impact statement as part of their 1997 relicensure, however. This document led to new guidelines, adopted by PPL, which requires the dam's owner to not only continue to operate Holter Dam as a run-of-the-river dam but also to maintain water levels behind the dam within a certain range. In January 2011, as part of its management efforts, PPL agreed to donate $1.2 million to fund 41 conservation projects along the Missouri and Madison rivers, which included restoring and increasing riverside vegetation along 4.5 miles (7.2 km) of the Missouri River below Holter Dam and a study of the walleye feeding habits below Holter Dam.
Drought has also affected the dam's operation. No water was permitted to flow over the dam in 1986 due to drought. In 1992, water flowed over the dam's crest on only a single day. In wetter years, water flows over the dam almost continuously. A severe drought struck the state of Montana beginning in 1999. By May 2004, the dam was permitting only 3,500 cubic foot (99 m³) to 3,000 cubic foot (85 m³) per second downriver. These flows were well below the 4,100 cubic foot (120 m³) per second needed to keep the fishery healthy. The low water flows, coupled with whirling disease, led to a 40 percent drop in big fish (those over 17 inches (430 mm) in length) as well as lower overall numbers of fish immediately below the dam. A 2005 proposal by the managers of the Helena National Forest to draw down Holter Lake by 2 feet (0.61 m) in August 2005 in order to repair Coulter Campground near the Gates of the Mounta
Holter Dam