Field data sheets for the semi-quantitative samples (RTH and DTH) (fig. 15 for instream habitat sampling and fig.16 for snag habitat sampling) are divided into eight sections. The first five sections are identical to the first five sections of the QMH fi eld data sheet (fig. 13) with the following two exceptions: the mesh sizes differ and there is an additional line in the "SAMPLING INFORMATION" section of the semi-quantitative sampling field data sheet. This line, "Number of samples constituting compos ite," is used for entering the number of individual samples that were collected to form the composite sample that characterizes the sampling reach. This number should be five or greater.
The sixth section of the semi-quantitative sampling field data sheet shown in figure 15, "INSTREAM HABITAT TYPE SAMPLED," is similar to the corresponding section of the QMH field data sheet in that it contains information on the instream habitat type samp led and the sampling equipment used. However, unlike QMH sampling, semi-quantitative sampling (RTH and DTH) is done in only one instream habitat type using a single sampler type. The instream habitat type sampled is indicated by checking the boxes that correspond to the appropriate geomorphic channel unit, channel boundary, and channel features that define the habitat type. The code for the sampler used is entered on the last line of the block. The "SAMPLER CODES" section, the seventh section, is identical to the corresponding section on the QMH field data sheet.
Space is provided in the "INSTREAM HABITAT TYPE SAMPLED" section (labeled "Other") for describing an instream habitat type that does not correspond to any of the 51 instream habitat types described by the habitat matrix. This provision is designed to address those rare instances when a sampling reach contains a highly unusual instream habitat type that fits the definition of RTH or DTH but cannot be described using the existing instream habitat matrix (fig. 2). This provision is to be used conservativel y and in consultation with the regional biologists, North Carolina Ecology Group, and national synthesis teams.
The last section of the RTH and DTH field data sheet (fig. 15), "MICROHABITAT CHARACTERIZATION," is for recording information on the water depth, current velocity, type of current meter used, and substrate characteristics associated with each of the sampling locations from which samples were collected for the composite sample. Water depths are measured either directly using a meter stick (wadeable sites) or indirectly using a depth finder (nonwadeable sites). Current velocity is measured at six-tenths of the water depth for wadeable sites or at two- and eight-tenths water depth at nonwadeable sites (separate counts and seconds with a '/' on the data sheet and check the type of current meter used). When velocity measurements are made at two- and eight-tenths water depth, the two values are averaged and recorded in the velocity column. Depths and velocities are obtained prior to positioning the sampler. When possible, these measurements are taken at a representative point, avoiding large rocks, eddies, and other features of the sampling area that would yield nonrepresentative results within the area to be sampled, or at multiple points within this area, if time permits (record average depth and velocity). If this is not possible or if the measurements would disturb the sampling site, then the measurements are made in an adjacent area with similar characteristics.