EDARP
Project Review Comments
- Project Name
- Crystal Park Site S-75(R) - Site Plan
- Description
- Site plan approval for new home construction in Crystal Park. Geologic review required per building restricted area.
- Location
- Parcels
- 7418000207 7418000207
- Applicant
-
Palace Homes Inc
Gordon Stegner ( Gordon@palacehomesinc.com )
(719) 632-9635 Gordon Stegner ( Gordon@palacehomesinc.com )
(719) 632-9635 - File Number
- CP234
- Project Manager
- Ashlyn Mathy
- Status
- Closed
- Created
- 12/2/2021 5:16:41 PM
View: Project Documents
| Agency | Comment | ||
|---|---|---|---|
|
PCD Project Manager
7/12/2023 9:33:36 AM |
please be sure to get he CGS payment as this site was in the preservation area, and staff was told ina meeting it would be moved but into the hazard area. | 7/12/2023 9:33:36 AM | |
|
Colorado Geological Survey
7/11/2023 2:01:47 PM |
The referral documents included the Site Plan and Elevation Plans (Palace Homes Inc., 6/8/2023) and Soils Report (Geoquest, LLC, 12/15/2021) for the proposed residence at 5961 Waterfall Road. The referral documents include multiple addresses: 5961 Waterfall Road, 75 Waterfall Trail, and 5986 Waterfall Trail. The address of 5961 Waterfall Road depicts the site to the east and south of the mapped location displayed on the location map for S-75 and site plan. CGS used the coordinates 38.8285, -104.9372 in our review. If this location is incorrect, we should be notified. The Geoquest soils report excludes a discussion of the geologic hazards associated with the site (as required per Section C.2 - Geologic Hazards Report of the El Paso County Engineering Criteria Manual). CGS recommends a geologic hazards study be prepared for this site, if this study has not yet been performed. The proposed building is located upslope of a drainage that feeds into Crystal Park Lake. The proposed building area is associated with a relatively gently sloping area. The site does not contain steep slopes, rockfall hazards, or mapped landslides, nor is it exposed to any geologic hazards that preclude the proposed residential structure. Based on the site plan showing existing grades, 12 to 24 percent slopes are descending towards the site from northwest to southeast, and 1041 hazard mapping describes these slopes as stable. Rockfall potential exists west of the project area, and a large boulder is south of the proposed house. The site is underlain at variable depths by relatively loose material (commonly known as “Grus” or “Colluvium”) weathered from the underlying Pikes Peak Granite. Pikes Peak Granite is typically not problematic from a geotechnical or foundation performance perspective. However, the rock is fractured and weathered, sometimes extensively. Both of these rock quality characteristics can impact slope stability and erosion potential. Additionally, Grus is weaker than the bedrock and can be highly variable in depth and highly susceptible to erosion. Geoquest’s characteristics of the subsurface conditions and geotechnical recommendations are valid. Provided a geologic hazards report has been prepared for this lot, and Geoquest’s recommendations are strictly adhered to, CGS has no objection to the site plan approval. CGS offers the following comments and recommendations during the planning and development of this site. 1. A rockfall hazard is mapped to the west of the site. As previously stated, the bedrock at the site is the Pikes Peak Granite. Bedrock outcrops upslope and to the west of the proposed residence could result in a rockfall hazard. The existing rock outcrops should be examined and monitored before and during construction activities. Any loose rocks should be removed during construction. 2. CGS recommends that all planned cuts exceeding four feet in height be evaluated for slope stability using proposed slope geometry and considering all foundation and proposed cuts that will affect the slope. The geotechnical engineer should be provided with the construction plans and grading information to verify the proposed slopes. 3. Retaining walls, building foundations, and upslope foundation walls that will function as retaining walls must be designed by a qualified geotechnical, structural, or civil engineer and include adequate behind-wall drainage. 4. The site plan indicates that a leach field (septic location) is planned to the east of the proposed residence. Engineered septic systems are commonly used in the Crystal Park area due to the steep slopes and geology. Geoquest did not mention the existence of groundwater or fluctuations of groundwater in their report. 5. Site drainage should be designed and constructed to prevent concentrated flows from being developed within the site. It is imperative that water is allowed to drain quickly and NOT pond anywhere within or near developed areas. Proper maintenance and erosion protection of the slope face within the subject property is critical to the long-term structural integrity of the proposed structure. 6. Based on topography maps, a drainage is located south of the site. Scour protection and erosion control measures should be implemented during construction near the drainage. 7. Geoquest should be contacted during construction to perform an open hole observation. Submitted 7/11/2023 by Amy Crandall, Engineering Geologist, Colorado Geological Survey (303-384-2632 or acrandall@mines.edu) |
7/11/2023 2:01:47 PM |