A Water Quantity Monitoring Network consists mainly in field stations that gathered data about the hydrological cycle parameters (rainfall, evaporation, run off, soil infiltration and water storage in the aquifers). The water quantity monitoring network is expected to provide support for decision making and watershed management activities such as :
- Estimate of the present situation and trends in terms of flood and drought and provide data to calibrate models that may show the impact of change in land use (e.g. deforestation, reforestation) on flood (mainly flash flood) and dry season flow. Indirectly, information related to erosion and sediment transport may be developed as well. Eventually, it should give better guidelines for selecting critical areas where strong conservative measure to protect (restore) forest, water and soil should be a priority.
- Establish up to what extent water allocation rules must be developed if the context shows critical situation in terms of water availability, this being especially applicable during the dry season. In this respect, the definition of minimum flow to be maintained in the streams during the dry season must be considered.
In addition, the water quality monitoring network should support :
- Calculation of peak flow to be considered when building water infrastructures (spillway, weir, bridges, culverts,…)
- Fine tuning irrigation efficiency by providing better estimate of evapotranspiration. This will be mainly applicable in case of development of new irrigation technologies (drip irrigation, sprinkler) and help increasing efficiency of irrigation.
- Get progressive understanding of the contribution of the groundwater system for maintaining of the Nam Ton base flow and identify possible critical areas where tapping of groundwater or resurgences should be better regulated. Check opportunities and threats of using groundwater resources.
- Provide information related to the contribution of the Nam Ton as part of the tributaries of the Mekong basin.
The table below is a summary showing the topic that can be addressed by the Water Quantity Monitoring network, the related equipment and a quick overview of the methods to be used for data treatment.
|
Topic |
Equipment |
Possible data treatment |
|
Present situation and trends in terms of flood and drought |
Automatic Water Level Stations, Climatic Stations |
Observation of time series (rainfall and flow) Modelling land use change (SWAT model) |
|
Water allocation rules |
Staff gauge, groundwater observation, raingauge |
Observation of time series (base flow, contribution of tributaries) Modelling water balance (HEC model) |
|
Peak flow |
Climatic Stations, Automatic Water Station (for models calibration) |
Rainfall curve (intensity, duration, period of return) Various methods of calculation (unit hydrograph, SCS, HEC model,…) |
|
Irrigation efficiency monitoring |
Climatic Station |
Evaluation of evapotranspiration and crop management (CROPWAT model) |
|
Get progressive understanding of the contribution of the groundwater system Opportunities and Threats |
Groundwater observation, Staff gauge |
Observing value and trends of the lowest discharge and try to correlate with value and trends of groundwater level. Likely to be quite intuitive. |
|
Contribution of the Nam Ton as part of the tributaries of the Mekong basin |
Automatic Water Level Station (Houeykham) |
Data could be integrated into the MRCS HYCOS system |