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HomeMy WebLinkAboutPN_SWARRNarrative_260611_v11 PROJECT NARRATIVE Puget Sound Energy SWARR Station Security Perimeter Maintenance Project I. Project Location/Parcel Details Site Address: 2100 Benson Drive South, Renton, WA 98055 Section-Township-Range: SW 20-23-5 Tax Account #: 202305-9071 Subject Parcel Zoning: Residential-8 (R-8) Adjacent Parcel Zoning: To the west (across Benson Drive South) zoning is R-8; to the east (across South Puget Drive) zoning is a combination of R-14, RM-F and CA; to the north (across intersection of S Puget Drive and Benson Drive S) is R-14 and R-8; and to the south is R-8 and RM-F. Comprehensive Land Use Designation: Residential Single Family Parcel Size: 16.71 Acres Current Use: Peak Shaving Facility that provides supplemental capacity to the natural gas system during periods of peak demand or system disruption. II. Site Description Puget Sound Energy (PSE) developed the SWARR Peak Shaving Facility (SWARR) in 1965. The parcel is approximately 16.7 acres, with site improvements limited to the central portion of the property, covering an area approximately 5 acres in size. The developed portion of the site consists of a level area with turf grass, buried tanks, outdoor processing equipment, a single-story building, access driveways and small parking area. With the exception of the south side of the parcel, which borders single family residential property, the entire site is bordered by South Puget Drive and Benson Drive South. SWARR has an existing chain link perimeter fence topped with barbed wire that encloses the developed area. The fence is antiquated and damaged in places, and a number of security breaches have occurred in recent years. To protect the property and associated critical infrastructure against unauthorized access and other threats, PSE is proposing maintenance and repairs to the physical security perimeter. The northern portion of the property, beyond the fenced developed area, contains a wooded ravine. Rolling Hills Creek flows south to north in an open channel and the city of Renton identifies the stream as fish bearing perennial, with a 115 foot buffer in this portion of the property. Within the central developed portion of the site the stream is culverted. The stream daylights again into an open channel on the south side of the access driveway. South of the access drive, the riparian area is vegetated with a combination of understory vegetation, maintained grass, and trees scattered along the south property line. No disturbance or impacts will occur in the daylit portions of the stream or its buffer. On the south side of the site the fence will be realigned from the current location over the daylit portion of the stream to a new location at the edge of the access road where the flow is contained within an existing culvert. Refer to the Stream Assessment Report for more information. The city of Renton mapping (COR Maps) identifies a number of geohazard areas on the site, including Erosion Hazard, Landslide Hazard and Coal Mine Hazard Areas. These potential hazards have been evaluated by PSE and documented in a Geologically Hazardous Areas Report. 2 III. Project Description The proposed project consists of replacing the existing 6 to 7-foot high chain link perimeter security fence with an 8-foot to 12 foot tall metal mesh fence, and updating the associated security systems to meet current standards. The new fence will be topped with a 4-inch anti-climb ‘dental strip’, replacing the existing 3-strand barbed wire. The length of the replaced fencing is approximately 2,133 linear feet, and it will be located interior to the existing fence, reducing the footprint of the fenced area. The existing fence will remain in place during construction to provide site security. Following installation of the new fence, portions of the existing fence located within 10 feet of the new fence will be removed. Gates and Access The project includes replacement of existing gates and installation of additional gates for maintenance access. The existing 25.5-foot-wide motorized primary vehicle gate will be replaced with a new 24-foot- wide motorized double swing gate in the same location, including replacement of the gate operator equipment and card reader stanchion. The existing 14-foot-wide manually operated secondary vehicle gate will be replaced with a new 16-foot-wide gate located approximately 5 feet interior to the existing location. A new 20-foot wide manually operated double swing gate will be installed on the north side of the main entrance to straddle existing Williams Northwest Gas Pipelines. Two existing 5-foot-wide pedestrian gates will be replaced with new 4-foot-wide gates, and four additional pedestrian gates will be installed for maintenance equipment access at various locations around the perimeter. Refer to sheets 17, 18 and 19 of the civil site plan for locations and sheets 5.01 to 5.14 of the Betafence plans for details on the new and replaced gates. Signage Safety information signs required by public service companies do not require a sign permit per RMC 4-4- 100 B.6(q). The security signage proposed as part of the SWARR project consists of No Trespassing signs, facility identification information for emergency response, and other signage required per state and federal regulations. More information can be found on the Signage Plan in the civil site plan set (Drawing No. E002). Security Systems The security system upgrade includes replacement of the current camera system for complete perimeter and grounds coverage. Fifteen camera poles will be integrated into the new perimeter fence line, consisting of thirteen Super Posts (15' to 20' height) and two Tech Posts (15' height). The existing cameras will be decommissioned and replaced with state of the art cameras to ensure adequate detection and forensic capability. An intrusion detection system will be installed on the upgraded perimeter fence and gates. Network equipment will be upgraded as needed to support the camera and intrusion detection systems. Refer to sheet 7.20 for Super Post details. Electrical and Communication: Electrical conduits will be enclosed in the rails or mounted on the new fence to provide power and network to the camera poles and intrusion detection systems. This approach is intended to minimize extensive grading and site disturbance. In limited areas, conduit will be buried, including the interior length of all gates and removable fence panels, and from the west fence line to the northwest corner of the maintenance building. 3 Stormwater Management: The new fence will cross an existing roadside drainage ditch that is lined with a segment of half-pipe. To mitigate security risks at this crossing, a 20-foot section of the roadside half- pipe drainage ditch will be replaced with 12-inch diameter pipe, consistent with downstream sections that have demonstrated adequate capacity. Refer to the Stormwater Technical Information Report for SWARR Station for more information. The project does not include changes or additions to driveways, parking areas, or off-site improvements beyond the security perimeter upgrades described above. A minor change in existing elevations is necessary in an isolated area north of the entrance gate to accommodate a new gate. Refer to sheet 16 of the civil site plan for more information on proposed land disturbance. IV. Vegetation Impacts and Tree Removal A preliminary Tree Retention Plan has been completed by Davey Resource Group for the proposed work zone along the fence alignment. A total of three hundred two (302) trees were inspected. A summary of the findings include two (2) trees in excellent condition; ninety (90) trees in good condition; one hundred thirty-one (131) trees in fair condition, and seventy-nine (79) trees in poor, very poor or dead condition. Of the three hundred and two (302) trees inspected, two hundred and forty-eight (248) qualify as significant, and thirty-five (35) may meet the definition of landmark tree per RMC 4-11-200. The report recommends that 42 trees should be removed prior to construction for safety purposes, due to dead/poor/very poor condition. An additional 17 trees will need to be removed to accommodate project construction and operational needs. To ensure proper clearance from the new perimeter security fence, existing tree limbs will be pruned as directed by the project arborist, with clearance pruning anticipated to remove no more than 10% of the overall canopies of retained trees. Based on a preliminary assessment, there will be sufficient tree retention to meet or exceed the minimum tree credits required for the site. The proposed vegetation and tree removals are necessary in order to address vegetation maintenance concerns, ensure that the new physical security systems have line-of- sight to operate effectively and accommodate construction equipment. Critical root zone protections will be employed around trees to be retained; refer to the Arborist Report and sheet 16 of the civil site plan for more information.