Two separate multifunctional basins are available for scale model testing of pump sumps and other intake and outfall structures. Scale models still provide the best and most detailed answers to optimise these large civil constructions from a hydraulic point of view and to ensure a trouble free operation.

You have not yet indicated whether you want to accept or reject cookies. This means that this element cannot be displayed.

Change your cookie settings

Or go directly to:

Application areas

Prior to the scale model tests, an over-all quick assessment of the original design is carried out, often complemented with detailed CFD simulations (CFX). The scale model tests are realized in accordance with international standards such as ANSI/HI 9.8-1998, supported in-house knowledge and experience.


Our experience with physical modelling studies is considerable. We are involved in a wide range of intake and outfall structures. The following hydraulic phenomena can be studied and minimized during the scale model tests to ensure optimum hydraulic performance:

  • Global flow patterns in pump sumps: jets, pump submergence, dead zones, eddies, flow unsteadiness, head losses, flow non-uniformity, sediment settling
  • Pump approach flows: air entrainment, free surface and submerged vortices, pre-rotation, skewed approach flows
  • Outfall structures: air entrainment, eddies, dead zones, flow unsteadiness
  • Outfall transport pipes: (bio)fouling, transport of air pockets, head losses

Technical specifications

The Deltares IOS (Intake and Outfall Structures) basins 1 and 2 are available for model testing of almost any kind of hydraulic structure. The large IOS-1 basin has an area of 20×12.5 m2, and allows for cross flow in order to model (cross) channels or rivers. The smaller IOS-2 basin has an area of 6×16 m2 and allows higher water levels. In this way, smaller designs can be studied on a larger scale.

Share this page.