Some of us live in areas that get regular and frequent rain. Rather than running and plumbing water lines, digging a water pond could offer a nice feature to the pasture.

This pond installation was a fluke but it serves as a source of enjoyment for both the sheep and myself. At one time, many years ago, when my building was first built for the previous tenants, a water sump (Septic -- but only for grey water) was put in the place this pond now sits. Last year I discovered the sump after the sheep had sufficiently cleared the land so that the hole on the top of the septic lid was visible. One thing lead to another and we decided to dig out the sump to avoid possible future liabilities and questions about its use.

Supervising the sump removal I asked the contractor to leave the pit area as a watering pond. That made him happy because he was planning on purchasing soil to backfill the hole he dug; my request cut both his work and cost in half. As we spoke, I discovered that the contractor had owned American Blackbelly at one time and he offered and sloped the pond in a special way to help the sheep and retain the most water.

Just a simple sketch (above) shows that the pond has a narrow gentle slope leading to a broad and deep section of the pond. This allows at least one clear access point to the water without the risk of slipping into the pond when the pond level drops. The pond contains the greatest amount of water at the deepest part of the pond. It's difficult to see from the actual picture of the pond (above) since the pond is overflowing after a heavy rain, but it does look like the drawing with the deep end of the pond closest to the camera.
 
I've noticed that when the pond water lowers to almost half, the sheep will clearly walk down the path rather than try to lean over the steep walls of the deep end.


Keeping the water where it belongs (Seepage & Lime) -

Digging down several feet removes all of the organic decomposition, topsoil, sometimes even the clay layers found to be just below the surface. What remains is sometimes a thin or porous sandy clay or simply sand, perhaps loose rock or gravel depending on your area.
 
A natural pond has had many thousands of gallons of water sit in the pond over time, silt washing into the pond, and decayed leaves and plant life. All of these things have plugged the porous layer holding the water and therefore the pond or lake keeps the water with little seepage. In a NEW pond the water will quickly drain into the soil and you'll find that even after being filled by a heavy rain, after a few days the pond is once again empty.
 
To prevent seepage you can build up a quick layer of silt to plug the pores by adding LIME (Regular mason's lime used for mortar) to the pond or to the bare soil. The lime (Calcium Hydroxide) raises the pH of the water making it basic (Opposite of acidic). The high pH (Around pH 10.5 - 11) will cause the other dissolved metals carried by the water to fall out of solution as a microscopic solid (Read this). For example, the most common metal we see in water is iron. In acid, iron may appear slightly green or blue-green in water -- and in fact, many streams and lakes appear a deeper blue because of the additional; iron dissolved in the water.
 
As the pH of the water is raised iron will fall out, precipitate like rain, changing color to the normal orange-amber color you might see as rust. These microscopic particles fall to the bottom of the pond and plug the pores of the soil, helping to retain the water. At first the water may leak out, but after the pond has filled a few times and the layer thickens you'll see the results you need.


How much Lime?

For my pond (Above - 10 x 10 ft) I used a full bag of lime (~40 lbs). I spread it evenly over the entire surface of the bottom of the pond. As the water filled the pond and drained a couple of times, the pond eventually held water. As long as I don't disturb the bottom layer when it's dry, I won't need to add more lime.

 
Does Lime hurt the sheep?

There are several drinks we enjoy that are in the same pH range that the lime will raise your pond pH to. The lime in no way hurts the sheep and the taste of the water is not affected by the lime addition. In fact, I noticed that the pH of the pond remained high for many months and I saw many types of water bugs and frogs use the pond several weeks following it's first being filled.


Ecosystem of a Pond

Almost immediately after filling the pond you'll notice many visitors and new residents. Water spiders, water beetles, algae, weeds, frogs, and a host of other insects including mosquitoes and dragon flies. My first year in this pasture (before the pond) was horrible since we had a large number of small standing ponds and mosquitoes are a normal problem for my area. However, a few months after the pond the mosquitoes all disappeared as frogs, pollywogs, and dragonflies and their larva started to make a remarkable boom in population and fed on the mosquitoe larva. I was very pleased the next season having seen my poor sheep being eaten alive by hundreds of the blood suckers the year before.

As the pasture was cleared there were far fewer places for the mosquitoes to live and breed. That, and the increase in mosquitoe predator's, made standing in the pasture pleasurable even during the wet months. In time I also found that some migratory birds brought in a few water plant species but none of these have so far taken over the pond. Algae also exists in the pond in small quantities on the warmest and most shallow area of the pond but it doesn't affect the pond significanty.



Advantages of a pond
1) Water is always available      
2) Water lines are not needed
3) Dragon flies - mosquito abatement
4) Frogs - mosquito abatement
5) Pleasant scenery
6) Low cost
7) Can be installed in remote locations
8) Visits from other animals (Raccoon, Armadillo, Birds)
9) No daily, weekly cleaning of water trough

Disadvantages:
1) Possible spread / source of parasites  -   See Coccidiosis
2) Drought can play a role in flock health
3) Water stagnation
4) Seasonal freezing/heated water
5) Infrequent but yearly cleaning, maintenance, and initial effort required