Conducting other site investigations
To determine if your site is restorable you need to discover if, when, and how it was drained. If your site was drained, you need to know by what means to help determine how to reestablish hydrologic conditions. The most common hydrologic alterations are ditching, drain tile, diversions, and channelization. Most sites have experienced a combination of several modifications; for example, rows of drain tile running to a ditch. If there are no obvious drainage features on the landscape, you may need some assistance to determine whether the land has been drained.

Another significant disturbance on many sites is sedimentation, or siltation, caused by eroded soils transported in runoff following rain or rapid snow melt. It is common to find sediment deposits completely burying original wetland soils, particularly in wetlands downslope of cultivated agricultural fields or in floodplains. Eroded soils are carried to the lowest point in the landscape, generally wetlands.

To determine whether sedimentation has occurred on your restoration site, you need the following tools to assess the site: a spade, a post hole digger or soil probe, and strips of lath or wooden wedges to mark the edge of the sediment layer. Dig a series of holes from the interior of the wetland where you think there is no sediment towards the upland slope where you suspect there is sediment. Look, as you dig, for a change in color and texture between the soil layers or profile. The sediment tends to be brown with fine loose particles, horizontally stratified (as if deposited in layers), and has no sands or gravels. The buried wetland soil should be a characteristic black or very dark gray color. Peats or muck soils will be very black, spongy, and once water is squeezed out, very light in weight. Buried wetland mineral soils will be black to very dark gray in color. Depending on the soil types, there may be a very visible line where this change takes place, for example a distinct color change where a brown silt overlays a black muck wetland soil. Push a wedge or wood strip "shim" into the side of the pit at the boundary between soil layers (see photo at right), and measure and record the depth to the boundary.

Flag your pits so you can locate them again. Dig several lines of pits to determine the depth of sediment across the site. If the sediment is deeper than you are able to reach by hand digging, you can try to determine the depth of wetland soil using a soil probe at the bottom of the pit. Keep careful notes of the position of each pit and the depth of sediment. To accurately determine the former topography of the wetland before the sediment was deposited, you need to have your site surveyed. The surveyor needs to take two elevations at the soil pit: the elevation of the existing ground surface next to your hole, and the elevation of the original soil, which is where you placed the shim. Using these elevations you can draw two cross-sections for your site- one that shows the existing grade and one that shows the original grade. The difference between them is an estimate of how much soil needs to be removed if you want to restore the original basin.

Seed Bank Assessment- For thousands of years wetland plants have produced and dropped seeds into the soil of your wetland. Sometimes, under the right conditions, recent seeds buried in wetland soils or under sediment may be viable (living) but dormant, even if the site has been cultivated for decades. Seeds have been know to be dormant for up to 80 or more years. These living but dormant seeds comprise what is called the seed bank. By removing sediment overburden or restoring the original hydrology, you may provide the right conditions for dormant seeds to germinate.Does your site have dormant seeds ready to sprout once you have restored the site? The more living seeds you have, and the closer the site is to other diverse wetland sites that can serve as a source of new seed, the fewer new seeds or plants you will need to introduce into your restoration project.

To determine if you have viable seed in your seed bank, take plugs of soil just below the litter layer to test for germination. If you are planning to strip off sediment during restoration, take the plugs from the wetland soil layer that will be exposed. Take a number of samples from across your entire site. Use clean implements for collecting the soil from across your site so that you do not contaminate the samples. Take the samples home or to a reliable nursery for help. Spread the sample thinly, less than 1/4 inch deep, over sterile potting soil. Allow to grow exposed to light and water regularly so that the flats are kept moist. You may require some help identifying what seedlings come up, but even if you don’t know the species name, just knowing that sedges, rushes, and wildflowers are germinating as opposed to reed canary grass will be of great use as you proceed with your plans.