Planning level concept and Water Management Units (WMUs)

IWMR Vietnam is based on two structured underlying thoughts that have been developed within the R&D project:

  • The planning level concept lets us differentiate based on institutional responsibility and detailing demands for the separate types of information.
  • Water management units are the basic spatial units on a river basin level. They are homogeneous areas taking into account natural phenomena as well as human influence.

Planning level concept

The planning level concept facilitates an examination of entire river basins (planning level river basin), which is layered and problem oriented and efficient at the same time, in an overview exploration (scale approx. 1:300,000) to define “Water Management Units” (WMUs) with increased problem intensity and prioritized call for action (hot spot areas). All recent eE+E IWRM activities can be assigned to one of the planning levels.

Figure 2 depicts the underlying planning pyramid with five stacked planning levels.

Figure 1: Planning levels for IWRM in Vietnam (blue background = Planning and Decision Support Tools have been developed on the river basin level; exemplary IWRM measures have been implemented on local level)

International guidelines
This planning level is used to develop international IWRM guidelines. Main stakeholders are e.g. the GWP, UNESCO, the World Bank and the Asian Development Bank. On this level IWRM principles are developed and discussed critically.

National Laws / Policy
The national planning level in Vietnam serves to determine the river basins with an increased need for action, in which reconstruction measures must be carried out first. For Vietnam, this assignment was carried out during production of the Water Sector Review (ADB 2009) by the Department of Water Resources Management of the Vietnamese Ministry of Natural Resources and Environment (MoNRE-DWRM) with the help of foreign consultants (ADB Asian Development Bank). One of the results was the pinpointing of three prioritized river basins (e.g. Dong Nai) with discernible water management problems, especially relating to water quality.

River basin
This sub-project chiefly acts on the planning level river basin. Here the goal is to determine water management units with increased need for action regarding hydrological balance and water quality and to prioritize these. Water management units are sub basins of consistent topography, land use and hydrological characteristics.
Water Management Unit (river sub basin)
This planning level is used to name specific water management measures on the basis of detailed inquiries in order to remedy the discovered problems and to make decisions on specific locations (monitoring, waste water disposal, drinking water generation etc.).

Local level
The local level is used to carry out object planning (monitoring, waste water disposal, drinking water generation etc.) at the previously pinpointed locations within the areas with increased need for action.

Water Management Units

The processed river basins have been split into Water Management Units for IWRM (WMU). These are areas divided by watersheds, which may consist of several sub basins and which may be subjected to consistent management concepts due to their characteristics. Water use, water transfer and reservoirs are considered here.
The border of a WMU represents the system border of a management unit under consideration of the overall concept of integrated water resource management. Within the WMU aspects of water volume management and aspects of water quality management are considered equally.
Sub basins can be joined up in WMUs under the following conditions:

  • The WMU size is between 150 and 2,500 km².
  • The WMU borders represent watersheds of river basins or river sub basins.
  • The WMU division occurs under consideration of hydrologically significant regional characteristics (tributaries of the main stream, accumulation lake etc.), of land use and of geomorphology of the area under consideration.
  • In hollows and lowlands, in which river basins cannot be distinguished easily, WMUs are divided based on main waterbodies and canals or polders.

Based on the definition of WMUs, areas with homogeneous characteristics are laid out, with which the local population can identify on the basis of contiguous similar land and water use. Under this aspect the WMUs have been given names based on the names of rivers or the names of reservoirs. The names have been agreed with local authorities.