Negative of a photographic postcard showing the Mill River Power Plant at the River Mill Dam in Estacada, Oregon. Water from the Clackamas River goes over the spillway in the background. Power lines carry electricity from the plant. Handwriting on negative reads, "Mill River Power Plant - Estacada, Ore. Christian 11-6007."

Negative of a photographic postcard showing the Mill River Power Plant at the River Mill Dam in Estacada, Oregon. Water from the Clackamas River goes over the spillway. Handwriting on negative reads, "Mill River Power Plant - Estacada, Ore. Christian 11-6010."

Photograph taken from the top of Dam 1 at Bull Run. The dam features a decorative railing, gatehouse, and light posts along the top. At the center of the dam are three closed gates. A logged hillside can be seen in the background (negative 11 of 31).

Cascading water viewed from inside a doorway at Bull Run. Likely taken from a dam structure, water can be seen flowing down a river surrounded by trees (negative 17 of 31).

Photograph taken from a distance showing Dam 1 at Bull Run. A decorative railing, gatehouse, and light posts can be seen at the top of the dam, beyond which a reservoir can be seen (negative 26 of 31).

An aerial view showing the Willamette River in Oregon City, looking south. A dam can be seen at Willamette Falls, with a Portland General Electric hydroelectric power plant visible on the right side of the river. Roads are on either side of the river. Photographed with a K-25 camera (negative 2 of 14).

An aerial view showing the Willamette River in Oregon City, looking south. The Oregon City Arch Bridge crosses the Willamette River, to the west of Main Street. Willamette Falls, and a Portland General Electric dam and hydroelectric power plant can be seen on the river to the south of the bridge. Streets and houses in a grid pattern are on the east side of the river. Photographed with a K-25 camera (negative 3 of 14).

Photograph showing the construction of the spillway at the River Mill Dam. At the left side of the frame, a portion of a wooden suspension bridge can be seen. Behind, a railroad bridge spans the space between two cliffs, beyond which wooden buildings are visible. Written on the negative is “#84M. 1-28-11.”

Photograph looking across the Clackamas River, of a potential dam site for the future River Mill Dam. A rocky cliff-face can be seen across the water, as well as tree at the top of the frame. Written on the negative is “Oct 22, ‘09, PES #2004.”

Photograph of River Mill Dam looking upstream. The powerhouse can be seen to the right of the large dam structure, with a smaller wooden building to the front. In the background, a distant railroad bridge can be seen.

Photograph of the River Mill Dam, showing recently cut trees and possibly dam structure under construction. Water can be seen at the front of the frame.

Photograph showing the left bank of the Clackamas River at the river Mill Dam, taken from the “island.” Near the center of the frame, two men in long jackets stand next to a surveying station. To the left, another man in a hat and jacket looks at the camera. In the distance, men can be seen working on the dam spillway. Written on the negative is “#70M. 11-28-10.”

Photograph showing the exterior of the River Mill Dam powerhouse, likely shortly after construction. Loose hillsides can be seen to the left and right of the building, with transmission lines throughout (image note: corner of glass negative is broken and missing).

Photograph of the interior of the River Mill Dam (Station M) showing heavy head gate machinery. Several rows of large gears are visible, and large windows can be seen on all walls.

Photograph taken from a side angle of the River Mill Dam and powerhouse, showing exterior of building and view of dam structure. Water from the Clackamas River can be seen moving over the dam, and trees and transmission lines are visible in the distance.

Photograph taken from the side showing water cascading over the River Mill Dam. Across the water, the powerhouse for Station M can be seen.

Photograph from the interior of Station M at the River Mill Dam showing governor #3 during a test. On the device is written “The Lombard Governor Co.”

Photograph of the River Mill Dam powerhouse taken from a high angle, looking downwards. In the background, the dam structure and transmission lines can be seen.

Photograph taken from a bridge and looking downriver at the River Mill Dam and powerhouse. The Dam structure can be seen on the left, with the powerhouse building on the right.

Photograph of the interior of the River Mill Dam (Station M) showing generator machinery. Written on the side of the front unit is “General Electric Company.” Three people can be seen in the photo, two of which are looking at the camera.

Photograph showing a loose hillside with railroad tracks and a gravel pit at the Big Sandy Dam (likely the Marmot Dam). Multiple men can be seen standing on and near the tracks. At the top of a hill is a small wooden structure and platform. Written on the negative is “B.S.56.”

Photograph taken from a hill looking downward, showing buildings, trees, and hills in the distance. Written on the negative is “0254.”

Photograph of Bull Run reservoir showing dike and temporary falsework for construction of intake. A man in a long coat and hat stands on the dike looking forward. In the background, trees and buildings are visible.

Photograph looking into penstock tunnel at Bull Run. Wooden structure and train tracks visible down length of tunnel.

Photograph showing construction at the Big Sandy Dam (likely the Marmot Dam). Several workers are visible on top of the wooden dam structure next to the Sandy River. Uphill are several small wooden platforms and buildings. Written on the negative is “BS-20.”

Photograph taken from a high angle showing the penstocks at the Little Sandy Dam. In the distance, numerous utility poles and electric lines are visible. Construction debris litters the ground throughout the image. Written on the negative is “0346.”

Photograph showing men in work wear standing next to a large Y shape penstock. The metal penstock is seated on long pieces of wood with visible writing on different sections. A railroad track can be seen crossing through the front of the frame.

Photograph showing men in work wear standing on top of a wooden structure with rounded forms. Written on the negative is “intake 2-5-12.”