Waterman Civil & Transportation Group (WCT) was one of the original 12d Model
software users in the UK and have finalised an initial study for a housing
development of 3000 homes at Waterlooville on the South Coast of England.
This study involved a detailed assessment of flood risk in the area. The
Environment Agency had done rough flood outlines based on a 50m grid using the
Flood Studies Report, but a detailed assessment was required for planning to
determine the existing flood plain and to compare this with another ‘post
development' flood study.
For cost and speed, aerial photogrammetery was ordered to cover the entire site
and local surveyors were used to locate the property boundary using traditional
means. The resultant photogrammetery (dgn format) and boundary (dxf format) were
merged into a single 12d digital terrain model of several hundred thousand
To obtain finer detail of the river and to verify the model of
the plain, further detailed river cross sections were then surveyed. In the
office, work began on building the HEC RAS project inside 12d Model.
After ensuring concurrence on hydrological methodologies with the local
Environment Agency office, WCT carried out the back water hydraulic study.
Graduate Engineer and 12d user Richard Russell said, “Using 12d with HEC RAS I
was able to devote more time to sensitivity tests in HEC RAS and in 12d. I had
the luxury of time to try different roughness coefficients and to test if ground
cover picked up with the photogrammetery had a significant impact on the
results. This gave us better confidence in the final results”.
addition to creating the HEC RAS project, 12d Model was used to present the
water level results. Detailed drawings were produced for submission to the
Environment Agency. Internally the visualisation abilities in 12d allowed quick
checking at all stages including the final water levels.
for WCT, Stuart Aldridge, commented, “12d cut the time taken for this type of
study significantly. This was the first time we had used 12d for flood modelling
and we were very impressed.
“Previously, significant resources were
devoted to what I now view as laborious and unnecessary data entry. We also get
to use survey data at a much earlier stage, which is proving useful on such a
big development. We still propose a detailed survey for a later date, but for
now our client can defer the significant cost of the survey until much later.”
While WCT and their client were benefiting from using 12d
Model on this project, the two other parties involved also had the opportunity
to see 12d in action on a live project. Although both have different interests
and uses for 12d, surveyors Julian Brotherton & Partners and the Environment
Agency were both impressed with 12d’s quick manipulation of data and 3d
abilities. Within a few months both parties became 12d users themselves.
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