Computer-aided estimates of drainage charges - a Dutch case study.
DOI:
https://doi.org/10.18174/njas.v26i3.17088Abstract
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)Downloads
Published
1978-08-01
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Papers