Regional hydrological model selection

and data requirements

Anna Johnell

Activities, Project Document

“This would include preparing a set of criteria for

selecting the two to three hydrological models for

supporting the impact assessment, followed by a

review of existing hydrological models for potential

application at the regional level.”

Selection criteria

The model should be one that can be applied over a range of catchment

sizes from large to global

The model should have been used for water-balance studies

Adequate sophistication to simulate all relevant hydrologic processes,

including arid area processes. In particular interactions between surface

water and groundwater flows, and estimation of evapotranspiration.

Representation should also include the river flow network.

Should be able to output daily values

The minimum input data requirements for the model must be easily

available (data-poor catchment).

The model should be able to use data from various global databases.

The model must be readily and freely available with available

documentation

Hydrological Models

1. ACRU

South African model used in semi-arid areas

Multi-purpose model hydrology, crop yield,

irrigation.

Small to medium sized catchments

2. HBV

Swedish model developed at SMHI

Catchment scale model

3. HEC-HMS

American model

Catchment scale model

Several options for modelling runoff,

baseflow, river flow and meteorology

Hydrological Models

4. HYPE

Swedish model developed at SMHI

Improved water quality routines

Better in using spatial data

5. Mac-PDM

Global model developed in the UK

Simulates runoff on a gridded basis

6. VIC

American model

Large scale catchments

Models on a grid

7. WaterGAP

Global model

Gridbased, uses data from global databases

Coputes withdrawl and consumption of

water

Other Hydrological Models

Nile-DST, Sacramento model

Database

River simulation and management

Agricultural planning

Hydrologic modeling, Sacramento model

Remote sensing, and User-model interface.

Others?

Input data

Precipitation

Temperature

Evaporation

Elevation data (mainly for defining watershed)

Soil type

Land use (special interest could be irrigated areas)

Large lakes, surface area

Rating curves

Dams, reservoirs and its use / regulation

Diversions / bifurcations - that is, if the water takes a different path than the one given by the

topography

Desired data

Groundwater, major aquifers

Lengths of rivers

Flow measurements (almost a requirement)

Water level measurements

Information on soil depth

Etc.

Whist – a tool for

automated creation of

subbasin data

(geophysical inputs)

Uses global

databases, but

improves

with local data

WHIST, World Hydrological Input Set-up

Tool

Nile basin Detail from Nile basin

Global Databases

Topography: Hydrosheds (from USGS)

Lakes: Global Lakes and Wetlands database (GLWD)

Land use: GlobCover Land Cover

Soil: Soil map of the World, UNESCO, 10 km

Local knowledge important!

Hydrological Simulation System

HYSS

Data regarding model set-up e.g.

number of watersheds, areas, soil layers

etc.

Needed observations for the given

timestep

State variables

Variables for model parameters

Time variables

Variables for storage of result

Constants

Specific variables

Hydrological model

Definition of model parameters

Definition of result variables

Sets values for result

Model run for one timestep

Initial values for state variables,

förberedande calculation of parameters

Preliminary Recommendations

Hydrological models (2-3 to be choosen)

1.HBV or HYPE

Used at SMHI

Source code available, can be included in HYSS

2.VIC

Extensive use in many regions

Source code available, can be included in HYSS

3. ??

Input data

Use WHIST and global databases

HYSS to make the hydrological modelling more efficient

Good DATA for calibration IMPORTANT especially river discharge and groundwater!

Thank you for your attention!