Habitat Scoring Guidelines

Guidelines for Scoring Habitat Criteria

The stream quality survey has a second page that asks you to define the immediate environs of the stream. This fills in the picture of your monitoring site. Guidelines for answering each question are presented below.

Fish water quality indicators – Some fish, like trout, are sensitive to pollution. Others, like carp, are relatively tolerant. Unless a fish happens to wind up in your net they are not easy to identify without experience. In answering this question you should first look at general characteristics: are the fish seen individually or in schools. Once this is done and you are relatively certain of the type you can note which fish you see. Not all the possibilities are given here.

Barriers to fish movement – This should specifically note barriers within a short distance of your monitoring site, not those more than a mile off.  If you have a barrio not listed, please check other and write in the barrier type present at your site.

Surface water appearance – Please indicate the color of the water itself, apart from the substrates.  This indicates 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 lead to 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) – Please 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 of 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 – Notes invisible but 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. It also helps keep track of the quality of the riffle.

Alga color and location – Please note first the color of the algae (make sure that you are looking at the algae itself and not any sediment on it), then estimate the area covered by algae.  Algae growth is responsive to nutrient loads. An increase in alga growth is a sign that nutrient loads may have increased. Color and consistency of the algae also indicate excessive nutrient loads. A matted or hairy alga is a sign of low stream quality. Light or dark green algae in spots indicate a healthy stream. Brown algae often indicates episodic increases in sediment loads.

Stream channel shade – Please indicate the shade present on the day you monitor.  The shade cover will be lower in the winter and fall in areas of deciduous trees.  There is no need to make note of this fact – biologists will be able to tell the season based on the date. 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 (=100%) – Please 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. Much of the sediment load in a stream comes from eroding stream banks. 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. The percentages you record should be those in the immediate vicinity of your monitoring site.

Stream bank erosion potential – This 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 those rocks lying on top.  Stream bottoms are not static; they do change through time. The composition of a riffle can shift during heavy flooding, even moving downstream much as a sand dune moves downwind. 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 smooth feeling 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 between 1/64" and ¼" in size. Gravel consists of all rock between ¼" and 2" in size. Boulders are those rocks greater than 10" in diameter. At times some riffles may have exposed bedrock. Since this is a poor habitat for macroinvertebrates you should note this 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 of stream quality even though the land use does not use a great deal of land, such as a construction site which 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.

When considering land use as the controlling factor in stream quality, look beyond the area visible from your monitoring site. All the land that drains into the stream has potential to impact stream quality. This is your watershed. If the stream drains an intensely developed area you should not be surprised if few or no organisms are found in your survey. If you are in an agricultural zone where farming or grazing is practiced right up to the stream, you may find indicators of organic pollution. Should either of these be the case, consider testing a stream that passes through a closed forest for a sampling comparison. You will probably find the difference quite startling.  Sources causing poor or fair stream quality include sewage treatment plants, industries, construction sites, sewer overflows, landfills, mining operations, high urban runoff, and streamside agriculture. Sampling the stream at regular intervals upstream from the initial sampling point until quality improves can isolate a pollution source. The pollution sources should be located somewhere between the point of quality improvements and the last location where degraded conditions were found.

Describe litter – Many streams downstream of urban areas are dumping grounds for refuse. While not necessarily pollutants, they can degrade, causing pollution or simply be an aesthetic nuisance. Noting which types 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 briefly add any thoughts, opinions, or observations you have made about stream health that are not included in the form.