So, what the heck is a Dry Hydrant?
A dry hydrant is a simple plumbing fixture with the potential of big returns. It is one of those safety items that you hope will never get used...like a smoke alarm. And, like a smoke alarm, it is also one of those safety items that can pay for itself in multitudes within moments.
City folk don't even consider the possibility that there may not be water available to put out a fire. Country dwellers know better. Liberty is nowhere near any fire hydrant...until now. The pond will be an exceptional source of fire-fighting water....and lots of it! Your average fire pumper can tap right into a pond and pump it out to where it is needed. A dry hydrant simplifies this operation by providing a pre-established hydrant source from which to draw water.
This above pic is a good example of a dry hydrant. It is a PVC pipe that starts fairly deep within the pond, runs through the bank, and pops up on dry land, reasonably near a road. A filter is placed on the end within the pond to keep junk out of the draw. A terminal fitting is placed on the dry end that will match up with the pumper hose that the local fire-fighting unit uses. It is basically a fire hydrant that is not under pressure.
We have elected to install a 6" PVC pipe for our dry hydrant. We have also decided to minimize the bends required to raise the pipe above the embankment by using 45 degree fittings (instead of 90 degree fittings like the example above).
Use of the 45 degree fittings will provide 3 benefits: a) less drag while critical volume is rushing through the pipe b) a slightly shorter pipe length c) If there is ever a problem with attaching the pumper hose to the fitting (frozen, stripped, wrong size, etc), the fitting can be hacked off and a smaller pumper hose can be inserted directly into the pipe. It should readily slip past the less obstructive 45 degree fitting to reach the static water level within the pipe.
This pipe run is 100 ft horizontal, below grade to reach the pond. The riser pipe on the 45 degree angle is 20 ft long. We will leave it long and unfinished for now...the last 45 degree fitting and the appropriate terminal fitting will be attached later when the entire surrounding excavation work is completed. The other end is a different story. This will someday (soon?) be under water. We will want to move that one up a little on the priority list. We are right now researching and preparing a purchase of a strainer intake.
The final, buried dry hydrant pipe:
The pond end of the pipe can be seen left-center of frame...the other end at upper right. The equipment is parked on the future building site. The (temporarily placed) rocks to the right are piled next to the boat launch road. This puts the dry hydrant in a narrow area directly between the boat launch road and the building site....not a bad location at all.
...a few weeks later, and we have completed the intake end of the dry hydrant system. A strainer unit was purchased from the same manufacturer that supplied the anti-seep collars for our pond drain line. It is permanently glued to the intake end of the dry hydrant pipe. It is about 3 feet long and has holes strategically engineered to size and pattern on the bottom half of the unit to maximize fluid passage suitable for the application. We opted for another bell and whistle; a spring loaded back-flush end-cap and the support holes with a stainless support strap.
Just before gluing the strainer into place, we dug a short hole with a clam-shell posthole digger directly below the location of the "support rod holes" in the end of the unit. We dumped in concrete to fill the hole, slid the 1" diameter aluminum support rod thru the holes and strap and into the fresh concrete. The stainless support strap is "springy" and binds against the aluminum rod, fully adjustable for height.
Once the concrete completely cures, we will cut off the excess support rod and paint the entire structure with latex paint to ward off U.V. damage while we wait for the water level to arrive. This strainer was installed at a depth of 6 feet below the normal pool.
** Note ** the 1" diameter aluminum rod was selected as grade 6061 for it's good corrosion resistance properties. We searched and located a 12' long piece, cut in half for U.P.S., for about $40 delivered.