The DOS-based TSLIB programs provide for data entry, analysis, and display of daily or monthly stream flow or habitat values. Minimal support is provided for these older DOS-based programs. These programs are provided for continuity in past studies and as a source of ideas for other analyses. A user's manual is available (see below).
Habitat time series can easily be calculated using a spreadsheet. Use of spreadsheets gives maximum flexibility in adapting the time series time step to the needs of a particular study. A sample habitat time series Excel spreadsheet HABTS.xls can be downloaded and adapted to most studies.
The premise of time series analysis is that the instream physical habitat at a given time and place can be calculated as a function of the streamflow using the equation
HA(t) = PH(Q(t))
PH( ) is the physical habitat-versus-streamflow function for a given life stage and species of aquatic organism or river activity;
Q (t) is the streamflow at time t; and
HA(t) is the habitat area for time t.
The physical habitat represents the space in a river that can be used as habitat by a given species and life stage of fish. The Time Series LIBrary (TSLIB) of programs has been developed to analyze the pattern of time-varying events.
The TSLIB system can be considered a decision support system with the decision being quantification of an instream flow need, an instream flow water right, or a minimum flow requirement for operation of a water resource project. The objective is to choose between water resource management alternatives or to modify the operation of an existing water resource system.
A system has been developed to simulate the physical habitat as a function of streamflow: the Physical HABitat SIMulation system (PHABSIM), described in Milhous et al. (1989). If PHABSIM is used to generate the habitat-versus-streamflow function, then the physical habitat is called Weighted Usable Area and PH( ) = WUA( ), where WUA( ) is the weighted usable area versus streamflow function.
Time series requires two types of data--streamflow data and the habitat-versus-streamflow function. The use of the TSLIB programs does not require that PHABSIM be used to generate PH( ), but it does require that the PH( ) function exist and be credible.
The streamflow time series is used to develop a physical habitat time series. A comparison of a streamflow time series to a habitat time series for the same site demonstrates the following two principles, which tend to be true in many regions and for many species:
Milhous (1983) advanced the concept that a physical habitat-versus-streamflow function can be used as a surrogate for an economic production function. In treating the physical habitat-versus-streamflow function as surrogate production function, the assumption is made that the value of the instream flows is proportional to the habitat produced by the flows. As with other economic benefits, it is desirable to know the time series of the benefits produced.
Waddle (1992), ("A Method for Instream Flow Water Management", Ph.D. dissertation, Colorado State University.) demonstrates an approach using habitat time series and basic survival measures to create a population-potential model. That model shows long term the recovery required after adverse habitat events. This "effective habitat time series" can be used to evaluate alternative water management plans.