REV02056 - Laserfiche WebLink

Home Browse Search

III IIIIIIIIIIIII III •~Berrp, David 999 From: Berry, David Sent: Wednesday, July 25, 2001 4:32 PM To: Mathews, Dan Cc; Cheryl Linden (E-mail); Brown, Sandy Subject: RE: roadside TR 36 and TR 37 Dan -Good summaries. My response follows: TR36- 1. lagree that the concept is appropriate, but I will have Boulay review that actual SEDCAD numbers to verify the arguement. 2. I will have Stark review the bond piece. 3. Your concern is valid. Please incorporate an appropriate question for the adequacy letter, as we discussed. TR37 - Looks good. I'll have Boulay review the hydraulics. I requested a one week turnaround from Boulay and Stark. David ---Original Message---- From: Mathews, Dan Sent: Monday, July 16, 2001 11:27 AM To: Berry, David Subject: roadside TR 36 and TR 37 Hi Dave. I have looked at these two TR's, which were called complete 6/28/01. I sent a copy of each over to you at the time of completeness. TR-36 was submitted in response to a revision order to address some concerns Mitch brought up during the oversite inspection. There were 3 items we requested Stover to address: 1. Pond 6 primary spillway concerns. The concern was that during high flows in Coal Creek channel, water would back up the pond outlet swale to above thge elevagtion of the primary spillway pipe outlet, and prevent proper functioning of the gated primary spillway and possibly the emergency spillway pipe (in which the primary is nested}. Stover included analysis demonstrating that the pond would contain the inflow from the 25/24 event with no discharge from emergency spillway (ie water level in pond would not overtop emergency riser). We had asked that he demonstrate that the emergency spillway would function properly under the conditions of a 25/24 event in the pond watershed, coinciding with a 100/24 event in the Coal Creek watershed. He concludes that a high flow event in the channel would probably bury the primary outlet in sediment (which has happened a couple times) but that the pond capacity is such that there would be sufficient time after channel water levels drop, to clean out the outlet channel and pipe, with no exceedances or discharge. Since pond would not discharge due to 25/24 event, there would not be a problem with functioning of the emergency spillway for that event. This is pretty much what I had assumed, and seems rationale to me. Do you agree? Do you want to have a hydrologist review the calculations? 2. Pond 6 and 10 reclamation. Additional detail, postmine topo changes, and volume information was provided as requested for pond final reclamation. Could you have Jim Stark amend cost estimate to reflect the modified reclamation volumes and source distances? 3. Channel berms. In our letter, we had asked Stover to amend the plan to clarify that "at no point along the segment between the dip section concrete structure at the upper end and the two, 81" by 59" road culverts at the lower end, should berms be utilized to provide the necessary flow capacity". Proposed page 14-3 submitted with the revision says "Berms located along the middle and lower sections of the channel will be leveled so the channel blends naturally into the adjacent terrain. Berms will not be utilized to contain the channel". So, for whatever reason, Stover chose not to use the specific language we had suggested. Do you want me to press for more specificity? TR-37 I think this one is pretty straight-forward. One of the cross-sections on the existing Map 58 for the 2-West Portals was mislabeled, with topo lines off by 1000 feet, and was corrected by the revision.