Open mhabimana opened 5 years ago
Key ref is WMO Guide to Hydrological Practices https://www.hydrology.nl/images/docs/hwrp/WMO_Guide_168_Vol_I_en.pdf Most of the measurements are simple to add to Climsoft, just by adding the entity types, because they are point location measurements. e.g. River height by staff gauge or still-well, volume flow through a gauging station. We already cover rainfall, evaporation (pan or Pichet), snow depth and water content (I think?), soil moisture deficit (which has location and depth as metadata) typically from a Neutron Probe or porous blocks. As with current station metadata, having a site plan and photos is important (staff gauges in particular are cheap and simple, but subject to being moved either deliberately or accidentally!) Height of water surface is the most common measurement specific to hydrology - this is point-specific (often the stations are co-located with rainfall stations). Lake and reservoir stations may record additional parameters including water temperature, salinity, acidity and other chemical concentrations. Probably the most complex instrument system is use of a current meter from a boat. Typically the boat will go across the river, taking measurements at intervals. Measurements will typically be taken at a number of depths as well. Hence the set of measurements will be at positions relative to a base station. This is analogous to the system we already have for radio-sonde measurements, so each datum has a location of its own, while still related to a base station. However, they are slightly more complex because the measurement depth would need to be relative to the river height at the time, so it is not absolute. Final aspect to think about is how to store areal data, including river catchment metadata and catchment average precipitation - so far we have only allowed for a catchment identifier, but nothing about mapping the catchments (though this is a generic shortcoming in Climsoft concerning areal data). One could regard this as derived data, and store it in a separate area, apart from the pure instrumental data. We will need to work this out for other uses - this is covered in WMO-1131, but not yet implemented. Next step is probably to get some hydrology specialists involved.
Asked Ulrich Looser at BADG. He replied: Hydrology is a wide field which covers several disciplines. I would like to focus on hydrometry, the part of measuring water level and discharge in rivers. The discussions with Matthias Adler, our hydrometry expert, resulted in basically four key variables which are recorded in hydrometry. W - Water level (at a gauge with a fixed zero reading) V - Flow velocity (various methods to determine this) A - Cross section of the water body at a given point (surveyed) Q - Discharge (calculated from the above values via a rating curve) In the attached document the table for these four variables can be found on page 209 in the section on “Discharge Rating Curves” from the publication “Manual for Water Level Gauging and Discharge Measurements” DVWK-Guidelines for water management ; 30, 1990. I have sent a copy via normal mail to you address at Met Office, as this document is not digitally available.
Matthias informed me that he is not aware of standard forms that are used for recording flow and depth measurements. Forms are either instrument specific or designed by the user.
I will follow up on AGILA and see if we can link to it.
This is a request for INAM ( Met-Mozambique) so that Climsoft can accommodate both Climate and Hydrological data.
There have been other requests to extend the use of CLIMSOFT to include hydrological data – river level, flow, catchment average precipitation.