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<br />7. 1. 2 As much as 5 or 6 hours from 1:he initial flood warning <br />may be required for Burlingt:on Northern t:o mobilize a train <br />and crew in Denver, travel t:o Wiggins and erect the closure <br />structure. In that case, the extra warning time provided by <br />the Highway 52 aut:omated flood detection gage would be <br />needed. <br />7.1.3 Having an automated gage at Highway 52, as well as ob- <br />server readings from that sit:e, provides an additional level <br />of security. In the event that the observer assigned to read <br />the staff gage was out of tmm or otherwis;e indisposed during <br />a big flood, the automated device would still initiate a <br />warning. <br />7.1.4 Two automated flood warning gages will permit the at- <br />tenuation of flood waves to be analyzed from Wiggins without <br />waiting for calls from observe.rs. Ac;curately determining the <br />attenuation of a flood betweEm Highway 52 and the County Road <br />Bridge will be crucial in making the decision to request a <br />closure of the Burlington Nort.hern levee gap. If the flood <br />is underestimated, t:here is a chance that: the railroad would <br />not be able to complete the closure in time. If the flood is <br />overestimated, an unnecessary closure of the railroad could <br />be made, which would cost the: Railroad a considerable amount <br />of money. <br />7.1.5 Two flood alarm gages provide an additional factor of <br />safety in the event that a severe s1:orm, greatly different <br />than the one assumed in the HEC--l model, strikes the basin. <br />Additionally, the 2 gage syst.em, coupled with accurate re- <br />cording of flood peak magnH:ude and timing, will allow the <br />flood warning system to be calibra1:ed after a few floods. <br />This calibration will improve flood forecasting accuracy over <br />time. This leads to the second recommendation given in Part <br />7.2. <br /> <br />7.2 Data Collection <br />7.2.1 A chronological lis1:ing of main1:enance and system <br />tests will aid in keeping 1:he system running accurately. <br />Data on battery charging and voltage readings will be par- <br />ticularly helpful in determi.ning when to charge and ulti- <br />mately replace the gel-cel bat:teries. <br />7.2.2 All flood events should be recorded in the gage log <br />book. Data should include 1:he time that each alarm was re- <br />ceived. Additionally, the peak stage from the flood should <br />be determined from high water marks and its approximate time <br />of occurrence recorded. This data will allow rough flood <br />hydro graphs to be developed 1,vhich, over time, can be used to <br />improve flood forecasts. <br /> <br />26 <br />