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<br />Statement <br />Number <br /> <br />6400 <br /> <br />6790 <br /> <br />6840 <br /> <br />6870 <br /> <br />7185 <br /> <br />Notes and Remarks <br /> <br />TRIAL AND ERROR FOR CHANNEL Q FAILED. For the low flow and <br />weir flow combination, the discharge through the channel must <br />be determined. In trying to determine the discharge through <br />the channel by an iterative process, the assumed and computed <br />discharges do not agree in 50 trials. The allowable error <br />of 1 percent is too severe for the computation or a programming <br />inadequacy has been detected. <br /> <br />20 TRIALS OF EG NOT ENOUGH. In determining the energy grade <br />line elevation for a combination of weir flow and low flow, <br />the discharge computed for an assumed energy grade line ele- <br />vation could not balance with the actual discharge to be used <br />in the water surface profile determination. When this condi- <br />tion occurs, the job should be rerun using the trace feature <br />and the cauae of this failure determined. <br /> <br />FLOW IS BY WEIR AND LOW FLOW. The minimum top of roadway in <br />one or both overbank dips below the low chord over the bridge <br />and the resulting water surface elevation, which is below the <br />low chord over the bridge, was computed using Class A low flow <br />under the bridge and weir flow in the low overbanks. <br /> <br />D.S. ENERGY OF X HIGHER THAN COMPUTED ENERGY OF Y. The pre- <br />vious cross section's downstream energy grade line elevation <br />of X is higher than the current cross section's computed <br />energy grade line elevation of Y. The current energy grade <br />line elevation was computed for a combination of weir and low <br />flow or weir and pressure flow. The energy grade line eleva- <br />tion for this cross section has been assumed equal to the <br />previous energy elevation in order to eliminate negative <br />losses. The weir coefficients used apparently were too <br />efficient. <br /> <br />MIN SPECIFIC ENERGY. The computer determined that it was <br />impossible to procede from the previous cross section to <br />the current cross section without crossing critical depth <br />and therefore, critical depth has been assumed for the current <br />cross section. In other words, maximum losses cannot produce <br />an energy elevation as high as the minimum energy at critical <br />depth. If this note occurs for several consecutive cross <br />sections, it is apparent that the wrong type of flow (IDIR) <br />has been assumed for this segment of the profile. The cross <br />section should be reversed, IDIR changed and the profile run. <br /> <br />Exhibit 7 <br />Page 7 of 8 <br />