Urban Hydrology

Every city has a its own hydrological cycle of precipitation and inflow, storage and losses, and runoff, and differences between these cycles over the world are enormous. In the basis, however, urban hydrology is about two central themes: public health and keeping dry feet.Because local circumstances vary so much, designs of urban hydrological systems also vary greatly. There is no standard blueprint. Factors such as soil characteristics, surface elevation, precipitation characteristics, the requirements and availability of fresh water, organizational elements and budget restrictions are parts of the puzzle that must be weighed and valued.

drainage & sewer plan

Municipal sewer plan for the city of The Hague
The Dutch city of the Hague has an extensive sewer system that ensures healthy living in the city. The system that collects and removes sewage and rainwater encompasses about 1,400 kilometres of underground pipes and features 30,000 inspection shafts under the city’s streets. Some of the sewer pipes date from 1880 and are still working. The “Municipal Sewer Plan The Hague” was developed to monitor the system and replace infrastructure were required. The plan outlines the strategy dealing with various sewer and urban water problems and, most importantly, provides the (financial) justification and means to ensure the performance of the system.

discharge model studies

modelling of drainage and discharge of urban stormwater
Discharge model studies are a tool to calculate the collection and discharge of stormwater in urban areas in time and place. This information can be used for feasibility studies within the context of rainwater harvesting. These calculations are compounded by measurements and combined into a coherent and manageable process supporting the decision maker.

drainage systems modelling tool

modelling tool for surface discharges
In the early 1990’s, Dutch municipalities were committed to improve the poor quality of surface waters with for instance detention tanks. NIVO/GM was developed as a reservoir modelling tool to assess sewer system discharges to surface waters. NIVO was an important design tool to improve the performance of detention tanks, which were a major measure to retain polluted storm water. An important feature of NIVO was the possibility to validate the reservoir model with detailed calculations of a sewer system. In these detailed calculations the 1:1 configuration of a sewer system (the individual pipes and manholes) were taken into account.