Describing the Immediate Environment (Habitat Assessment)
Directions - Describing the Immediate Environment (Habitat Assessment)
The final portion of the monitoring session is to evaluate the habitat of the stream. This is an important portion of the monitoring because it can help identify sources of pollution and stressors to the macroinvertebrate population.
- Fish water quality indicators. Some fish, like trout, are sensitive to pollution. Bass are somewhat sensitive. Others, like carp and catfish, are relatively tolerant. Unless a fish happens to end up in your net, you may find it difficult to determine the fish's species without experience. However, certain general clues may help in identification (e.g., are the fish seen individually or in schools?). If you are relatively certain of the type, you can note which fish you see.
- Barriers to fish movement. You should specifically note barriers within a short distance of your monitoring site, not those more than a mile off. If you have a barrier not listed, please check "other," and write in the barrier type present at your site.
- Surface water appearance. You should indicate the color of the water itself, apart from the substrates. This may indicate runoff problems. Most streams are clear in periods of low flow. At high flow, runoff is more likely and may change the color and/or clarity of the water. A tea color often indicates the presence of tannins in the water from decaying leaf matter. A colored sheen may indicate an oil spill of some kind. Otherwise discolored water indicates erosion or other types of runoff upstream from your site that could lead to lower or changed macroinvertebrate populations.
- Streambed deposit (bottom). You should indicate the color/type of material in the substrate in the riffle you sample. In most riffle monitoring the bottom will consist of gravel, cobbles, and boulders. In some cases there is a layer of muddy material between the cobbles that may increase or decrease through time. This is an indicator of the stream's sediment load and type of sediment. Noting the color and/or consistency of this sediment helps keep track of changes in the environment for macroinvertebrates.
- Odor. You should record any odors, because, although invisible, odors may indicate significant pollution.
- Stability of the streambed. Like the color or consistency of the streambed deposit, this is an indicator of sediment load and changes through time. Monitoring streambed stability also helps keep track of the quality of the riffle.
- Algae color and location. You should note first the color of the algae (make sure that you are looking at the algae themselves and not any sediment on them), then estimate the area covered by algae. Algae growth, color, and consistency are responsive to nutrient loads. Matted or hairy algae are a sign of low stream quality. Light or dark green algae in spots indicate a healthy stream. Brown algae often indicate episodic increases in sediment loads. It is important to indicate the stream channel shade present on the day you monitor. Shading is an important determinant of water temperature and oxygen concentration in the stream. Oxygen levels are higher in colder water. Sensitive fish and macroinvertebrates do better with higher oxygen levels. Shade quantity should be determined by estimating the overhead cover at the monitoring site. Only five choices are given: full, high, moderate, low, or none.
- Stream bank composition. You should estimate the percentages of each vegetation type based on the immediate bank (not the entire riparian area). All herbaceous plants and mosses should be included in grasses. The long-term stability of a stream bank is often determined by the makeup of its plant population. Bare banks are eroding. Heavily wooded banks seldom erode even in heavy flooding. By noting the percentage of cover provided by various components of the stream bank, you can keep track of changes through time that could affect stream health.
- Stream bank erosion potential. Erosion potential is a subjective estimate of damage to the stream bank through time. It is often comparable to the amount of bare soil, but not exclusively. If the height of the stream bank is greater than the rooting depth of the plants on it, erosion is a distinct possibility. This category is your estimate of the potential amount of the stream bank that could experience erosion during high rainfall or a flood event.
- Riffle composition (=100%). Please be sure to note all the substrate within the riffle, not just the rocks lying on top. Stream bottoms are not static; they do change through time. Riffle composition affects macroinvertebrates. The ideal habitat for many of the creatures is cobbles—stones between 2 and 10 inches in diameter. This estimate of composition percentage indicates the quality of macroinvertebrate habitat. Silt or mud is determined by feel. If the streambed bottom has a smooth feeling like mud, it is probably made up of silt and clay particles. When it feels gritty or has visible grains, then it is sand. In streams, sand grains are those particles 1/64 inch or smaller in size. Gravel consists of all rock up to 2 inches in size. Boulders are rocks greater than 10 inches in diameter. At times some riffles may have exposed bedrock. Because this is a poor habitat for macroinvertebrates, you should note any exposed bedrock in the comments at the bottom of the survey.
- Land uses in the watershed. The SOS Habitat Survey form asks if land use impacts are high (H), moderate (M), or slight (S). Although these questions are somewhat subjective, record the impacts the following ways: Note "H" for a land use if it comprises the majority of land in the watershed and is polluting the stream. Or, note "H" if the land use has a severe impact on stream quality even though the land use does not use a great deal of land, as in the case of a construction site that has caused the stream to be full of silt and muddy water. Note "M" for a land use if the land use is definitely contributing to stream degradation but is not the major cause for degradation or is one of many causes. For example, parking lot runoff and trash from a shopping mall may contribute significantly to stream pollution but may not be the only cause of stream degradation. Note "S" for a land use if its impacts are minimal in polluting the stream. For example, although a farm may be present, good farming practices and conservation measures may mean the pollution impact is negligible. If the land use is present, but causing no pollution, write "N" for none. Finally, leave the entry blank if you notice no forms of this land use upstream from your monitoring site.
- Litter. Many streams downstream of urban areas are dumping grounds for refuse. While not necessarily pollutants, these refused-filled streams can degrade, causing pollution or simply creating an aesthetic nuisance. Noting which types of litter and other refuse are present and how much of the stream area is affected may contribute to actions that reduce refuse disposal in the streams.
- Comments. Often the information given above needs further clarification. Use this last section to add briefly any thoughts, opinions, or observations you have made about stream health that are not included in the form.