Davis Hydro, LLC
A Davis Collaborative Company


The Nantanna Site is on the Dog River in Northfield Vermont.

Click on the pictures for high resolution version.

Powerhouse in Winter

The tailrace is on lower left, with the dam in the top left - mostly out of site. The transmission pole mounted transformer, and metering equipment is shown on the right. Behind the pole and off the picture to the right is the control room with the bakery above.

Dam in winter

Notice the two breaks in the ice dam on top of the flashboards. It is not uncommon to have an half foot of water or more behind a very fragile ice dam above the flashboards. It breaks often with rapid changes in discharge and pond levels. This happens typically when upstream ice dams break pushing surge of water downstream. Our control computer tries to keep the level constant.

Dam Internals

This shows the control ring that is used to change the attack angle of the guide vanes. This is an as-purchased photo. We are currently upgrading this installation with new control equipment - and paint!.

Generator # 1

Greasing the main bearing in the turbine is a regular task. The generator bearing is sealed. The cog belt is shown on top.

The green mounting frame allows belt tightening.

Left side of powerhouse

Picture taken in summer 2004. The Nantanna Mill chimney is in the background. The dam is on the left; powerhouse on the right; red penstock connecting them.

Since this picture, the roof has been repaired.

Right side of powerhouse

Picture taken looking west in summer of 2004. There is a bakery in the corner building above the control room. The powerhouse is the low sloping building on the left. The power comes goes out, and comes in, at the pole shown. Since this picture, the roof has been repaired.

Right side of powerhouse

This picture shows the stairs up to the dam top. The penstock is on the left. The bakery is behind the brick wall to the right of the stairs. The picture shows the top of the old trash rack cleaner. It has been replaced with a new one. We also installed all new control electronics and sealed conduit.

Millpond in Winter

This picture is taken standing at the trash rack. Ice is a limiting factor in the winter before it completely covers the river.

Two Turbines

The two hydraulic cylinders control the butterfly valves. Turbine #2 is visible at left center, and the edge of the top of turbine # 1 is at the lower left. The brown stain is leaking dried mud.

This and other interior pictures show the site prior to it being cleaned up.

Ice Dam in winter

In the winter the ice can pile up on the top of the flashboards raising the pond above the flashboards. In this photo the ice dam has given away on the left and far sides.

Flash Boards

The pond is lowered here for repairs.  Note teh carpet on the bottom of the flashboards to stop water leaking under the wood..

The Flashboard Pins

Here we are replacing the bent pins with new ones.  They are usually bent by trees going over the falls.

Looking Upsream

Note that the river is only 0-4 feet deep.

Looking Downstream

The water has been drawn down for cleaning the trash rack.  That's Jay Boeri at the clamshell controls.

The Site in Winter

20 below zero is not uncommon. 








© 2003, Davis Hydro
A Davis Collaborative Company

Web design/maintenance by Documagik