Some Like It Wet
direction it flows are important to know when planning a pool.
The amount of time water stands in a spot indicates the soil's ability to hold water after the pool is built. The direction water flows will indicate how dirt should be moved to avoid altering the natural flow of water. It's also important to know which way the water flows if you need to build a berm or small levee. However, many times levees are not needed when building ephemeral pools. Simply scooping out a low site may make a fine pool.
Ephemeral pools don't need much runoff water. The best locations are those that catch and hold water. If a series of pools is planned, connecting them will be important for water flow.
Try to build ephemeral pools near fencerows or blocks of forest so that salamanders and other slow-moving creatures can visit them without exposing themselves to predators.
Another indicator of a good pool site is vegetation. The types of vegetation present in an area can tell you whether a particular location is suitable for a pool. Smartweed, bulrushes, sedges and many other wetland plant species will grow in moist sites that provide adequate habitat for the kinds of creatures that colonize ephemeral pools. The boundaries of these areas are often clearly defined by where wetland vegetation stops and upland vegetation begins.
The topography or lay of the land, also marks where the pool may expand and contract. Pools wrap around higher ground to make points, and extend up into small "valleys." The varied contours of the shoreline provide a diversity of habitat. The floor of the pool should be irregular, not flat. This provides a mix of water depths for a variety of creatures.
Once a pool site has been located and the potential boundaries defined, construction can begin. Building pools usually requires machinery. A tractor out-fitted with a blade may be all you need to form a pool, but disking will loosen the soil and make it easier to move with the blade. Thick, deep-rooted plants make it hard to move dirt with light equipment. In that case, a small to medium bulldozer may be more appropriate.
Pool size depends on the site. An average pool may be 10 to 15 feet wide and 30 to 60 feet long, and the best ones will be no more than 20 inches in depth. However, smaller or larger pools are common and also produce valuable habitat.
In some situations it might be possible to construct a series of connected pools. These would simulate a meandering stream through which water would move during periods of high water flow.
Building ephemeral pools can be fun and rewarding. Identifying possible sites, designing the pools, and doing the actual dirt work all involve being in the outdoors and accomplishing work that will benefit many species.
Be careful to avoid locations that are already functioning wetlands. If there's any doubt about the status of a site, have it checked by a resource professional, such as a private lands conservationist.
Once it is built, you can make your ephemeral pool more user friendly to salamanders, crayfish, frogs and other wetland species. They need structure for protection. Good sources of ephemeral pool structure are sawmills. Ask for slabs (edges of trees that are cut off during sawing). These provide excellent places for small creatures to get under for protection. Trees and limbs also make good structure. Almost any tree or limb will work. Just lay the structure you have available in the pool area. The critters will do the rest.
One important characteristic of ephemeral pools is the fact that they usually contain water in spring and early summer. This is when many species of wildlife bear young. By the time the pools dry in mid to late summer, the young have grown large enough to travel to other water sources.
Even after ephemeral pools dry up, plants continue to grow there. These plants provide food and shelter for the animals that use the pool once it refloods.
The pools may reflood any time it rains, but spring rains commonly fill ephemeral pools, beginning the cycle again.
When it rains in early spring, salamanders move to ephemeral pools where they can breed and lay eggs. This short migration is sometimes called "running."
Each spring, salamanders migrate across a section of road near my home. Even though our kids are older, all four of us went this spring to watch the salamanders. We saw several on the road and 21 in a small ephemeral pool.
It wasn't on his birthday this year, but we still had a great time!