DSS is a database system that was designed to efficiently store and retrieve scientific data that is typically sequential. Such data types include, but are not limited to, time series data, curve data, spatial-oriented gridded data, textual data, and others. The system was designed to make it easy for users and application programs to retrieve and store data.

DSS data is stored in blocks, or records, within a file, and each record is identified by a unique name called a pathname. The pathname is formulated in a way that makes it easy to group related data together. Software from HEC has the ability to read from and write to DSS files. This capability facilitates data exchange among applications. For example, you could use HEC-ResSim to generate the time series data input for HEC-FIA. A pathname may consist of up to 391 characters and is, by convention, separated into six parts, which may be up to sixty-four characters each. Pathnames are automatically translated into all upper case characters. They are separated into six parts (delimited by slashes "/") labeled "A" through "F," as follows: /A/B/C/D/E/F/. Table 1 provides an example naming convention for regular-interval time series. A typical regular-interval time series might be:

/RED RIVER/BEND MARINA/FLOW/01JAN1995/1DAY/OBS/

The CWMS database uses a similar pathname concept, but has a set of Identifiers rather than using the ambiguous A through F parts. They also use dots, '.', instead of the slashes, '/', to separate the parts in the pathnames. When a CWMS database is open in CWMS-Vue the Pathname Filters display the CWMS identifiers. To search the CWMS identifiers use the Search By Part lists. Here the data can be filtered by the following parameters using their respective dropdown lists:

Table 1 DSS Pathname Parts

Part

Description

A

Project, river, or basin name

B

Location

C

Data parameter (e.g., FLOW, PRECIP)

D

Starting date of block, in a 9 character military format (ddmmyyyy)

E

Time interval

F

Additional user-defined descriptive information

  • Location – Physical location where data is collected.
  • Type – Indicates whether the reading is instantaneous, total (cumulative), maximum, minimum, average, or constant.
  • Parameter – Indicates the type of gage, such as precipitation or temperature. A hardwired list of parameter IDs are available in the CWMS database.
  • Interval – Specifies the interval between readings, or how often readings are taken.
  • Duration – Indicates how long it takes to record a data point; an instantaneous interval requires a duration of zero.
  • Version – Designates the data stream with which the time series is associated.