This presentation illustrates the many and various uses of AHPS that go beyond just flood forecasting and routine use by the emergency services sector.
The US 131 S-Curve project involved the reconstruction of 1.2 miles of freeway and six bridges that carry traffic through the city of Grand Rapids and over the Grand River. The S-Curve project required that the entire freeway be shut down for a little over a half a year, construction in the river and associated flood plain, and the partial removal of a flood wall in downtown Grand Rapids.
This is a birds-eye view of downtown Grand Rapids, Michigan and the US 131 “S-Curve”. The “S-Curve” project became necessary after a settlement of the river bed caused significant damage to the river bridge. The incentive/disincentive for the contractor was $50,000 per day for each direction of roadway. The contractor earned incentive for 19 ($950,000) days on the Northbound roadway and 35 ($1,750,000) days for the southbound roadway. As a result of the incentives/disincentives and working around the clock the project that normally would have taken 3 years to complete, was open to traffic in only 10 months.
The “S-Curve” project required equipment and people to work in and around the stream, with an access road built into the river. Worker safety was a top priority of the project manager and contractor.
The “S-Curve” project had over $ 2,000,000 worth of equipment on the causeway in the Grand River. The equipment consisted of trucks, drill rigs, cranes, pumps, and generators. All of this equipment would have to be moved off of the causeway during high water events.
The “S-Curve” project required the partial removal of the flood wall in downtown Grand Rapids to allow construction equipment access to the causeway built in the river. The contract required the removal of construction equipment and temporary replacement of the flood wall during high flows. This required accurate and timely hydrologic forecasts.
The Advanced Hydrologic Prediction Services (AHPS) played a significant role in the safe and timely completion of the S-Curve project. The S-Curve project used AHPS in the following ways: (1) probabilistic data and historical data helped the contractor plan and bid work; (2) provided daily plots of AHPS 5-Day forecasts which were posted on the wall in the construction site office; (3) during high flows, data was accessed via the internet several times a day by the project manager; (4) helped ensured worker safety in the floodplain; (5) helped determine movement and placement of heavy equipment in the floodplain; and (6) provided support for scheduling and construction of the bridge in and over the Grand River.
We had several high water events during the “S-Curve” project and received many complementary comments on AHPS forecasts.
Obviously with incentives/disincentives of $50,000 per day….every day was truly critical. The contractor made the most of AHPS and it paid off with $2,700,00 of incentives earned for completing the “S-Curve” project ahead of schedule.
With employees and equipment working in and around the river it was absolutely critical that they get accurate and timely hydrologic forecasts.
AHPS allowed the managers of the “S-Curve” project to avoid costly equipment damage, environmental pollution, unnecessary project delays and cost overruns, that could easily have occurred without accurate and timely hydrologic forecasts. The picture above was taken of another river bridge construction project that was about 10 miles downstream of the “S-Curve” project. It is a good bet that this contractor did not take advantage of AHPS. Several very expensive pieces of construction machinery were submerged at this site during the high water event. The high water event occurred in May with the river cresting about a half a foot below the flood stage of 18 feet in downtown Grand Rapids. The AHPS forecast for this high water event had almost 3 days of lead time and was within a half a foot of the actual crest. (River levels started at 6.9 feet and crested at 17.4 feet)
AHPS support of the Interstate 131 S-Curve Project in Grand Rapids, Michigan Mark Walton Service Hydrologist WFO Grand Rapids, Michigan
“ Although we could monitor river elevation on the cofferdam, the ability to predict when we would need to suspend work and flood it ( the cofferdams would have to be flooded when the river levels got high to prevent them from buckling ), was a great management tool and 2 nd check.”
“ Every day was critical, we found the hydrologic forecasts accurate within one day and many times even less on predicting a certain elevation .”
Equipment had to be moved up out of the river several times. “By use of the hydrographs we knew the causeways would be topped by several feet and it would do so within 8-12 hours. We built a temporary bridge that day to bring out the equipment… without an accurate forecast that day we could easily have had major equipment damage, release of oils into the river and the like. In fact I heard a contractor down stream had a loader flooded that day in the river.”
AHPS assisted project managers in their efforts to