Reaches One and Two extend from the confluence of the Jocko with the Flathead to just east of Dixon. The floodplain south of the active channel of Reach 1 has been converted to agricultural pasture, but to the north, the floodplain maintains diverse floodplain topography and vegeta-tion. Bank armoring and bridges have reduced floodplain connectivity. Reach Two has been impacted by local channel modifications, floodplain filling, the railroad and highway and grazing. Click on the buttons below beginning on the left to see how the river has changed.

My Image
    1937 Photo
    My Image

    About the 1937 Aerial Photographs

    Almost complete aerial photo coverage dating from summer 1937 and taken at a scale of 1:18,000 exists of the lower mainstem (USARS 1937). The US Agricultural Research Service took these images in a low resolution black and white format. In some cases they are quite dark, which makes it difficult to determine vegetation changes. Coverage is missing for two short sections of the river: (1) just downstream of the Highway 200 Bridge at Ravalli, Montana (the upstream end of Reach Three), and (2) almost all of Reach Seven (Jocko Hollow Canyon). However, despite these limitations, and the fact that the flights were made after the floodplain had already been significantly altered by human settlement, the photos provide the best aerial picture of the historic condition.

    1937 Impacts Mapped
    My Image
    scroll down

    Overview of 1937 Impacts

    By 1937—which is about 70 years after Euro-pean-American settlement began in the Jocko River Valley—the floodplain of the lower Jocko River had already been significantly altered by human settlement. Large areas of woody plant cover had been lost, and the railroad and high-way had been constructed. Both separated the river from the floodplain, and that had enormous impacts on the ecology of the river. As significant as these impacts were, many more were yet to come in the decades that followed 1937.

    Bridges
    There are three bridges in this reach: 2 railroad and 1 highway. The most downstream railroad bridge constricts over-bank flood flows and shallow, alluvial groundwater. Because of its location, it has a significant influence on the river and its stability. The second bridge has only a minor impact on the river—there is some upstream bank erosion, pier scour, and there are sediment transport problems, and the bridge is located on a meander, which makes it more vulnerable to erosion and deposition, but overall, the impact is minor. The Highway 212 Bridge does not significantly affect the river.

    Riparian Habitat
    In 1937, 75% and 59% of the floodplain of Reach 1 and 2 was covered by woody riparian vegetation, respectively. That is probably much reduced from what it was prior to 1900.

    Roads
    By 1937 some low-standard roads had been built within the floodplain for agricultural and residential purposes. Roads adjacent to the channel intercept and divert overland flows and can separate the river from the floodplain. Other roads were built to assist management of the National Bison Range. Unimproved roads can also add sediment to the river, whether or not they are in the floodplain.

    Railroad
    The railroad crossing marking the upstream extent of Reach 1, impacts the stability of the channel and floodplain. Floodplain fill for the railroad bed constricts the channel and disconnects the floodplain upstream and downstream of the grade. It confines flows to the channel and increases the floodplain surface-water elevation during flood events. It is likely that sediment deposition and debris accumulation occur upstream of the railroad crossing because it is undersized. In Reach 2, sediment deposition upstream of the railroad bridge may have contributed to a channel avulsion (an abrupt change in the course of a stream whereby the stream leaves its old channel for a new one). Although the channel has been shortened, the abandoned meander provides diverse off-channel habitats that benefit fish and waterfowl. The railroad bridge and raised railroad grade paralleling the channel in the upper half of the reach have also encroached on the floodplain and straightened the channel.

    Other
    Floodplain fill for the highway and railroad crossing abutments have converted the historical meandering stream type to a wider, shallower, and straighter stream type.

    2002 Photo
    My Image
    2002 Impacts Mapped
    My Image
    scroll down

    Overview of 2002 Impacts

    Bridges
    There are three bridges in this reach: 2 railroad and 1 highway. The most downstream railroad bridge con-stricts over-bank flood flows and shallow, alluvial groundwater. Because of its location, it has a significant influence on the river and its stability. The second bridge has only a minor impact on the river—there is some upstream bank erosion, pier scour, and there are sediment transport problems, and the bridge is located on a meander, which makes it more vulnerable to erosion and deposition, but overall, the impact is minor. The Highway 212 Bridge does not significantly affect the river.

    Channelization
    Fifty-five percent of Reach 2 has been channelized, and another 15 percent is affected by constructed levees. Some of the levees are constructed of vehicles cabled together. Although an individual feature like that may not influence overall channel stability, the cumulative effect of numerous channel confinement features can lead to reach-scale channel instability.

    Homes
    There are several houses on the floodplain in these two reaches, and there has been some channelization and riprapping to protect these structures and agricultural buildings from high water events. This has altered the hydrology of the river, reducing its access to the floodplain.

    Riparian Habitat
    In 1937, 75% and 59% of the floodplain of Reach 1 and 2 was covered by woody riparian vegetation, respectively. In 2002, those numbers had dropped to 41% and 47%. Much of the clearing was for agricultural purposes. In 2002, 30 percent of the floodplain of Reaches One and Two was agricultural land. In fact, the entire floodplain of Reach One south of the active channel has been converted to agricultural pasture. Riparian grazing along the southwest side of the channel in Reach Two has reduced
    riparian vegetation densities which, in turn, has reduced bank stability, riparian habitat, and stream shading.

    Roads
    By 2002 a number of low-standard roads had been built within the flood-plain for agricultural and residential purposes. Roads adjacent to the channel intercept and divert overland flows and can separate the river from the floodplain. Unimproved roads can also add sediment to the river, whether or not they are in the floodplain.

    Railroad
    The railroad crossing marking the upstream extent of Reach 1, impacts the stability of the channel and floodplain. Floodplain fill for the railroad bed constricts the channel and disconnects the floodplain upstream and downstream of the grade. It confines flows to the channel and increases the floodplain surface-water elevation during flood events. It is likely that sediment deposition and debris accumulation occur upstream of the railroad crossing because it is undersized. In Reach 2, sediment deposition upstream of the railroad bridge may have contributed to a channel avulsion (an abrupt change in the course of a stream whereby the stream leaves its old channel for a new one). Although the channel has been shortened, the abandoned meander provides diverse off-channel habitats that benefit fish and waterfowl. The railroad bridge and raised railroad grade paralleling the channel in the upper half of the reach have also encroached on the floodplain and straightened the channel.

    Other
    Floodplain fill for the highway and railroad crossing abutments have converted the historical meandering stream type to a wider, shallower, and straighter stream type.

    Channel Migration
    My Image
    Changes
    My Image
    Summary

    Summary of Changes Between 1937 and 2002

    Changes since 1937 have reduced the number of riparian acres and altered hydrologic processes:

    • Pools have become shallower,
    • There is less large woody debris in the stream and more
    sediment being deposited,
    • The floodplain is inundated or flooded less often,
    • Banks are less stable,
    • There is less shade and food for aquatic organisms, and
    • Stream temperatures have risen.

My Image

Reaches One and Two extend from the confluence of the Jocko with the Flathead to just east of Dixon. The floodplain south of the active channel of Reach 1 has been converted to agricultural pasture, but to the north, the floodplain maintains diverse floodplain topography and vegeta-tion. Bank armoring and bridges have reduced floodplain connectivity. Reach Two has been impacted by local channel modifications, floodplain filling, the railroad and highway and grazing. Click on the buttons below beginning on the left to see how the river has changed.

    1937 Photo
    My Image

    About the 1937 Aerial Photographs

    Almost complete aerial photo coverage dating from summer 1937 and taken at a scale of 1:18,000 exists of the lower mainstem (USARS 1937). The US Agricultural Research Service took these images in a low resolution black and white format. In some cases they are quite dark, which makes it difficult to determine vegetation changes. Coverage is missing for two short sections of the river: (1) just downstream of the Highway 200 Bridge at Ravalli, Montana (the upstream end of Reach Three), and (2) almost all of Reach Seven (Jocko Hollow Canyon). However, despite these limitations, and the fact that the flights were made after the floodplain had already been significantly altered by human settlement, the photos provide the best aerial picture of the historic condition.

    1937 Impacts Mapped
    My Image
    scroll down

    Overview of 1937 Impacts

    By 1937—which is about 70 years after Euro-pean-American settlement began in the Jocko River Valley—the floodplain of the lower Jocko River had already been significantly altered by human settlement. Large areas of woody plant cover had been lost, and the railroad and high-way had been constructed. Both separated the river from the floodplain, and that had enormous impacts on the ecology of the river. As significant as these impacts were, many more were yet to come in the decades that followed 1937.

    Bridges
    There are three bridges in this reach: 2 railroad and 1 highway. The most downstream railroad bridge constricts over-bank flood flows and shallow, alluvial groundwater. Because of its location, it has a significant influence on the river and its stability. The second bridge has only a minor impact on the river—there is some upstream bank erosion, pier scour, and there are sediment transport problems, and the bridge is located on a meander, which makes it more vulnerable to erosion and deposition, but overall, the impact is minor. The Highway 212 Bridge does not significantly affect the river.

    Riparian Habitat
    In 1937, 75% and 59% of the floodplain of Reach 1 and 2 was covered by woody riparian vegetation, respectively. That is probably much reduced from what it was prior to 1900.

    Roads
    By 1937 some low-standard roads had been built within the floodplain for agricultural and residential purposes. Roads adjacent to the channel intercept and divert overland flows and can separate the river from the floodplain. Other roads were built to assist management of the National Bison Range. Unimproved roads can also add sediment to the river, whether or not they are in the floodplain.

    Railroad
    The railroad crossing marking the upstream extent of Reach 1, impacts the stability of the channel and floodplain. Floodplain fill for the railroad bed constricts the channel and disconnects the floodplain upstream and downstream of the grade. It confines flows to the channel and increases the floodplain surface-water elevation during flood events. It is likely that sediment deposition and debris accumulation occur upstream of the railroad crossing because it is undersized. In Reach 2, sediment deposition upstream of the railroad bridge may have contributed to a channel avulsion (an abrupt change in the course of a stream whereby the stream leaves its old channel for a new one). Although the channel has been shortened, the abandoned meander provides diverse off-channel habitats that benefit fish and waterfowl. The railroad bridge and raised railroad grade paralleling the channel in the upper half of the reach have also encroached on the floodplain and straightened the channel.

    Other
    Floodplain fill for the highway and railroad crossing abutments have converted the historical meandering stream type to a wider, shallower, and straighter stream type.

    2002 Photo
    My Image
    2002 Impacts Mapped
    My Image
    scroll down

    Overview of 2002 Impacts

    Bridges
    There are three bridges in this reach: 2 railroad and 1 highway. The most downstream railroad bridge con-stricts over-bank flood flows and shallow, alluvial groundwater. Because of its location, it has a significant influence on the river and its stability. The second bridge has only a minor impact on the river—there is some upstream bank erosion, pier scour, and there are sediment transport problems, and the bridge is located on a meander, which makes it more vulnerable to erosion and deposition, but overall, the impact is minor. The Highway 212 Bridge does not significantly affect the river.

    Channelization
    Fifty-five percent of Reach 2 has been channelized, and another 15 percent is affected by constructed levees. Some of the levees are constructed of vehicles cabled together. Although an individual feature like that may not influence overall channel stability, the cumulative effect of numerous channel confinement features can lead to reach-scale channel instability.

    Homes
    There are several houses on the floodplain in these two reaches, and there has been some channelization and riprapping to protect these structures and agricultural buildings from high water events. This has altered the hydrology of the river, reducing its access to the floodplain.

    Riparian Habitat
    In 1937, 75% and 59% of the floodplain of Reach 1 and 2 was covered by woody riparian vegetation, respectively. In 2002, those numbers had dropped to 41% and 47%. Much of the clearing was for agricultural purposes. In 2002, 30 percent of the floodplain of Reaches One and Two was agricultural land. In fact, the entire floodplain of Reach One south of the active channel has been converted to agricultural pasture. Riparian grazing along the southwest side of the channel in Reach Two has reduced
    riparian vegetation densities which, in turn, has reduced bank stability, riparian habitat, and stream shading.

    Roads
    By 2002 a number of low-standard roads had been built within the flood-plain for agricultural and residential purposes. Roads adjacent to the channel intercept and divert overland flows and can separate the river from the floodplain. Unimproved roads can also add sediment to the river, whether or not they are in the floodplain.

    Railroad
    The railroad crossing marking the upstream extent of Reach 1, impacts the stability of the channel and floodplain. Floodplain fill for the railroad bed constricts the channel and disconnects the floodplain upstream and downstream of the grade. It confines flows to the channel and increases the floodplain surface-water elevation during flood events. It is likely that sediment deposition and debris accumulation occur upstream of the railroad crossing because it is undersized. In Reach 2, sediment deposition upstream of the railroad bridge may have contributed to a channel avulsion (an abrupt change in the course of a stream whereby the stream leaves its old channel for a new one). Although the channel has been shortened, the abandoned meander provides diverse off-channel habitats that benefit fish and waterfowl. The railroad bridge and raised railroad grade paralleling the channel in the upper half of the reach have also encroached on the floodplain and straightened the channel.

    Other
    Floodplain fill for the highway and railroad crossing abutments have converted the historical meandering stream type to a wider, shallower, and straighter stream type.

    Channel Migration
    My Image
    Changes
    My Image
    Summary

    Summary of Changes Between 1937 and 2002

    Changes since 1937 have reduced the number of riparian acres and altered hydrologic processes:

    • Pools have become shallower,
    • There is less large woody debris in the stream and more
    sediment being deposited,
    • The floodplain is inundated or flooded less often,
    • Banks are less stable,
    • There is less shade and food for aquatic organisms, and
    • Stream temperatures have risen.

Reaches One and Two extend from the confluence of the Jocko with the Flathead to just east of Dixon. The floodplain south of the active channel of Reach 1 has been converted to agricultural pasture, but to the north, the floodplain maintains diverse floodplain topography and vegeta-tion. Bank armoring and bridges have reduced floodplain connectivity. Reach Two has been impacted by local channel modifications, floodplain filling, the railroad and highway and grazing. Click on the buttons below beginning on the left to see how the river has changed.

    1937 Photo
    My Image
    1937 Impacts Mapped
    My Image

    Overview of 1937 Impacts

    By 1937—which is about 70 years after Euro-pean-American settlement began in the Jocko River Valley—the floodplain of the lower Jocko River had already been significantly altered by human settlement. Large areas of woody plant cover had been lost, and the railroad and high-way had been constructed. Both separated the river from the floodplain, and that had enormous impacts on the ecology of the river. As significant as these impacts were, many more were yet to come in the decades that followed 1937.

    Bridges
    There are three bridges in this reach: 2 railroad and 1 highway. The most downstream railroad bridge constricts over-bank flood flows and shallow, alluvial groundwater. Because of its location, it has a significant influence on the river and its stability. The second bridge has only a minor impact on the river—there is some upstream bank erosion, pier scour, and there are sediment transport problems, and the bridge is located on a meander, which makes it more vulnerable to erosion and deposition, but overall, the impact is minor. The Highway 212 Bridge does not significantly affect the river.

    Riparian Habitat
    In 1937, 75% and 59% of the floodplain of Reach 1 and 2 was covered by woody riparian vegetation, respectively. That is probably much reduced from what it was prior to 1900.

    Roads
    By 1937 some low-standard roads had been built within the floodplain for agricultural and residential purposes. Roads adjacent to the channel intercept and divert overland flows and can separate the river from the floodplain. Other roads were built to assist management of the National Bison Range. Unimproved roads can also add sediment to the river, whether or not they are in the floodplain.

    Railroad
    The railroad crossing marking the upstream extent of Reach 1, impacts the stability of the channel and floodplain. Floodplain fill for the railroad bed constricts the channel and disconnects the floodplain upstream and downstream of the grade. It confines flows to the channel and increases the floodplain surface-water elevation during flood events. It is likely that sediment deposition and debris accumulation occur upstream of the railroad crossing because it is undersized. In Reach 2, sediment deposition upstream of the railroad bridge may have contributed to a channel avulsion (an abrupt change in the course of a stream whereby the stream leaves its old channel for a new one). Although the channel has been shortened, the abandoned meander provides diverse off-channel habitats that benefit fish and waterfowl. The railroad bridge and raised railroad grade paralleling the channel in the upper half of the reach have also encroached on the floodplain and straightened the channel.

    Other
    Floodplain fill for the highway and railroad crossing abutments have converted the historical meandering stream type to a wider, shallower, and straighter stream type.

    2002 Photo
    My Image
    2002 Impacts Mapped
    My Image

    Overview of 2002 Impacts

    Bridges
    There are three bridges in this reach: 2 railroad and 1 highway. The most downstream railroad bridge con-stricts over-bank flood flows and shallow, alluvial groundwater. Because of its location, it has a significant influence on the river and its stability. The second bridge has only a minor impact on the river—there is some upstream bank erosion, pier scour, and there are sediment transport problems, and the bridge is located on a meander, which makes it more vulnerable to erosion and deposition, but overall, the impact is minor. The Highway 212 Bridge does not significantly affect the river.

    Channelization
    Fifty-five percent of Reach 2 has been channelized, and another 15 percent is affected by constructed levees. Some of the levees are constructed of vehicles cabled together. Although an individual feature like that may not influence overall channel stability, the cumulative effect of numerous channel confinement features can lead to reach-scale channel instability.

    Homes
    There are several houses on the floodplain in these two reaches, and there has been some channelization and riprapping to protect these structures and agricultural buildings from high water events. This has altered the hydrology of the river, reducing its access to the floodplain.

    Riparian Habitat
    In 1937, 75% and 59% of the floodplain of Reach 1 and 2 was covered by woody riparian vegetation, respectively. In 2002, those numbers had dropped to 41% and 47%. Much of the clearing was for agricultural purposes. In 2002, 30 percent of the floodplain of Reaches One and Two was agricultural land. In fact, the entire floodplain of Reach One south of the active channel has been converted to agricultural pasture. Riparian grazing along the southwest side of the channel in Reach Two has reduced
    riparian vegetation densities which, in turn, has reduced bank stability, riparian habitat, and stream shading.

    Roads
    By 2002 a number of low-standard roads had been built within the flood-plain for agricultural and residential purposes. Roads adjacent to the channel intercept and divert overland flows and can separate the river from the floodplain. Unimproved roads can also add sediment to the river, whether or not they are in the floodplain.

    Railroad
    The railroad crossing marking the upstream extent of Reach 1, impacts the stability of the channel and floodplain. Floodplain fill for the railroad bed constricts the channel and disconnects the floodplain upstream and downstream of the grade. It confines flows to the channel and increases the floodplain surface-water elevation during flood events. It is likely that sediment deposition and debris accumulation occur upstream of the railroad crossing because it is undersized. In Reach 2, sediment deposition upstream of the railroad bridge may have contributed to a channel avulsion (an abrupt change in the course of a stream whereby the stream leaves its old channel for a new one). Although the channel has been shortened, the abandoned meander provides diverse off-channel habitats that benefit fish and waterfowl. The railroad bridge and raised railroad grade paralleling the channel in the upper half of the reach have also encroached on the floodplain and straightened the channel.

    Other
    Floodplain fill for the highway and railroad crossing abutments have converted the historical meandering stream type to a wider, shallower, and straighter stream type.

    Channel Migration
    My Image
    Changes
    My Image
    Summary

    Summary of Changes Between 1937 and 2002

    Changes since 1937 have reduced the number of riparian acres and altered hydrologic processes:

    • Pools have become shallower,
    • There is less large woody debris in the stream and more
    sediment being deposited,
    • The floodplain is inundated or flooded less often,
    • Banks are less stable,
    • There is less shade and food for aquatic organisms, and
    • Stream temperatures have risen.