Linking meteorology and hydrology: measuring water balance terms in Cabauw, the Netherlands

Climate models need information about energy and water fluxes at the soil surface. In Cabauw (Netherlands) these fluxes and the belonging balances are measured. Water balances have been set up for a summer and a winter period to check the correctness of these fluxes. In winter precipitation is the largest input term and outflowing discharge the highest output term. In summer inflowing discharge is the largest input term and evapotranspiration the highest output term

Computer-aided estimates of drainage charges - a Dutch case study.

When regional water management is regulated centrally on a cooperative basis, methods must be developed whereby drainage charges can be estimated from agreed and objective data. Reported here is a method to compute and map, from data on altitude, the supposed open water level after a given discharge and soil characteristics for available moisture, the charges to be levied. Independent 'maps' are compiled for each of the three attributes by computer mapping techniques. The area is split into a large number of small cells (here 12.5 m X 15.5 m), for each of which the altitude is estimated by interpolation from known spot heights. For the same cells the supposed open water levels are approximated by interpolation from a number of calculated water levels in streams and ditches. Known watershed divides are introduced as barriers to interpolation. Four soil moisture classes are generated. The three 'maps' provide for each cell the basic data required by an allocation algorithm which evaluates the value for altitude, water level and soil moisture class. For each cell the appropriate drainage charge class was determined. A payment class map is generated by the allocation and can be printed on the computer lineprinter, each class being given a distinguishing printing symbol. The method is demonstrated for a 210-ha test area under the jurisdiction of the Regional Water Board Salland. Further extension to include a cadastral map to allow automated invoicing procedures are discussed. The system is implemented on a CDC Cyber 72 computer and uses SYMAP (Harvard University, USA) as one module. (Abstract retrieved from CAB Abstracts by CABI’s permission

Regenmeting met commerciële mobiele telefonienetwerken

Het is mogelijk om regen te meten met de bestaande infrastructuur die wordt gebruikt voor de communicatie tussen mobiele telefoons. De microgolfstraalverbindingen waaruit deze netwerken bestaan, zijn namelijk gevoelig voor regen. Zij kunnen als bron van neerslagmetingen daarom een zeer waardevolle aanvulling zijn op de operationele weerradar en regenmeternetwerken voor toepassingen in het waterbeheer. Deze toegevoegde waarde ligt in het feit dat regenintensiteiten geschat uit microgolfstraalverbindingen over het algemeen nauwkeuriger zijn dan schattingen naar aanleiding van radarbeelden en de dichtheid van het netwerk vele malen hoger ligt dan de dichtheid van regenmeternetwerke