T5 HEC-HMS

→ Graphical display of the basin model

• The basin map is used to develop a basin model.

• Hydrologic elements (subbasin, reach, reservoir etc.) are added from the toolbar and connected to represent the physical drainage network of the study area.

• Background maps can be imported to help visualize the watershed.

• Basin Model Manager

• Meteorologic Model Manager

• Control Specifications Manager

• Time-Series Data Manager

No canopy –> Interception

No surface –> Depression storage of impervious areas;

Initial and constant –>soil moisture storage

No transform –> runoff specifications, no transformation between two systems

No baseflow –> streamflow, that is not runoff, groudnwater

→ specifies the precipitation input required by a subbasin element

—> links the Rainfall of the Time-Series Data with the Subbasin

• Control or uncontrolled flood control reservoir regards the outlet of water in a reservoir, e.g. a dam

• uncontrolled flood control: outlet of water without regulating the flow, e.g. overflow spillway

• controlled flood control: outlet of water with regulating the flow, e.g. a gate or valve → for example control over quantity and (sometimes?) flow velocity

Controlled flood reservoir: outlet of water with regulating the flow, e.g. a gate or valve. A controlled flood detention basin can be used to model reservoirs, lakes, and ponds and is designed to represent a simple storage-outflow relationship.

1) Creating Reservoir

2) Implementing Data

3) Connect “reach”, “subbasin”, etc. to Reservoir per Downstream

4) Select Initial Elevation[M]

5) Select Discharge Gage

• Hydrological Modeling System

• Modeling tool for mapping water management systems

• available as open source program and can be downloaded for free on the internet

• developed by the American Corps of Engineers

• Functionality:

• Calculation of the basin-related runoff in response to precipitation events

• Calculation of runoff generation on the basis of different approaches

• Implementation of different unit hydrograph methods and the Kinematic Wave methods

• Runoff concentration with different calculation methods

• Basin

• time series data (start and end of rainfall event)

• description of the subbasin (total area, imperverious area, calculation methods, flow directions etc.)

• simulation time (start and end time) (Control Specification)

• meteorological model (precipitation data)

• connection to downstram area or component

• Terrain Data Manager

• Grid Region Manager

• Basin Model Manager → converts atmospheric conditions into runoff at specific locations in the catchment area

• Subbasin creation tool

• Reach creation tool

• Reservoir creation tool

• Junction creation tool

• Diversion creation tool

• Source creation tool

• Sink creation tool

• Meterological Models → determines the precipitation input required by a subbasin element; includes snowmelt & evapotranspiration

• Control specifications → controls the beginning and end of a simulation; specifies which time-interval is used for the simulation

• Time series data manager → input of for example precipitation gages or discharge gages

• Paired data manager → input of Storage-Discharge Functions or Elevation-Storage Functions

• Grid Data Manager

Initial and constant

• Direct runoff

• Does not show real conditions

• Peak discharge is much higher than the peak discharge of the soil moisture accounting

• Peak discharge is later

Soil moisture accounting

• Direct runoff, interflow, groundwater flow

• Peak discharge is much lower

• Peak discharge is much earlier

• Requires more information

• Select Method [Specified Release]

• Max discharge can be entered in Max Release [M3/S]

• Max Capacity can be entered in Max Capacity [1000 M3]