PC-2026-08 - Laserfiche WebLink

to turn around at a closed gate placed at the propsed staging/parking area? Furthermore, it is stated that 16 automobiles spaces and four horse trailer spaces will be provided in the parking lot. At the south parking lot (Tyler Ranch) I believe 74 spaces and three horse trailer spaces are provided. This is a substantial difference. How is the difference justified? Will the lack of parking spaces result in on-street parking? There is no mention of this issue or the problems that would be created if Park visitor parking were to occur on Dublin Canyon Road. An electric gate will be required for the Vinson/EBRPD driveway to keep the public from inadvertently entering the driveway. The EVA and emergency escape to/from my house and four ADU’s and the EBRPD fire crew house must be preserved and not in any way interfered with by the public using the Park. Hydrology The hydrologic response of a natural grass surface is very well understood. When rain falls on a natural grass surface, you have slower runoff, and a low peak flow. The hydrograph rises slowly, peaks at a relatively low flow and recedes gradually. With a paved surface there is no storage. Rain becomes runoff almost immediately. The smooth surface increases flow velocity and causes a higher peak flow. A large volume of water is delivered quickly. The hydrograph rises sharply, peaks much higher than the natural grass surface, and falls quickly. Greater erosion and the risk of downstream flooding occur. It is stated in the report that the project would have bio retention areas with sufficient capacity to ensure that the proposed project would not result in substantial erosion. This remains to be demonstrated, and in fact has not been demonstrated based on my observations of runoff from the paved areas in the Preserve housing development above two small canyons adjacent to the Vinson/EBRPD driveway. Stormwater runoff is “dumped” directly into the two small canyons, Canyons 1 and 2 (location shown below). A large volume of water is delivered quickly into Canyons 1 and 2. Figures 5 and 6 show the completely blocked inlet structures at the entrance to these canyons. Obviously, the inlet structures do not accommodate the high peak flows created by the paved tributary areas in the Preserve. Figures 7 and 8 show the runoff down the Vinson/EBRPD driveway at these two canyons. When the runoff reaches Dublin Canyon Road, it creates flooding across the road. Vehicles which drive through the high flood water covering the road create a “rooster tail”. This unfortunate situation has been created because the stormwater from the paved areas in the Preserve is “dumped” into these two drainages. When the inlet structures become filled with sediment and debris the subsurface stormwater drain system no longer functions. The City of Pleasanton owns the streets and stormwater drain system in the Preserve. The City accepted this poor design from the home developer (who actually created the problem) but of course the developer “walked away” from the problem. Now the City of Pleasanton “owns” the problem. I have contacted the City of Pleasanton regarding this matter and they have done nothing to solve the problem. The runoff down the paved area at the beginning of the driveway has T. Vinson Page 3 of 28 4 CONT 5