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Start of Item 40.
Message. Dated: 12/16/88 at 1056.
Subject: Pace Warehouse Geological Issues
Sender: Bob WILKINSON / CFC52/01 Contents: 2.
CC: Mike DAVIS / CFC52/01
Part 1.
TO: Tom PETERSON / CFC52/01
Linda RIPLEY / CFC52/01
CC: Mike DAVIS / CFC52/01
Mike POWERS / CFC52/01 / v, sue' 14
Brian WOODRUFF / CFC52/01
Part 2.
At your request I have attempted to pull together all available information with / Z 20
regard to the geology and fossil deposits on and adjacent to the Pace Hardware
site. This follows an issue which was raised at the neighborhood meeting last i5c ;
Thursday night regarding fossil deposits on the site. / J ""A"
With regard to City policies, goals, and regulations, the following seem to /;C4-
possibly apply:
GOALS AND OBJECTIVES
- Direct growth away from environmentally unique lands which cn be shown to
have special values to people - natural resource, scenic, recreational,
historical, unless the negative impacts can be effectively mitigated.
- Encourage developers to utilize natural contours, topographic features, and
existing trees where possible in accordance with the proposed use of the site.
LAND USE POLICIES PLAN
- Promote the incorporation of environmentally scarce and valuable lands,
including lands of agricultural importance into open spaces or historic
preserves.
LAND DEVELOPMENT GUIDANCE SYSTEM
- Criteria #12 and #28
GEOLOGIC INFORMATION
With regard to the deposits specifically, I have found the following:
According to surficial geology maps, the outcrop area is colluvium of the
Pierre Shale - clay, silt, and sand derived from shale, claystone, siltstone,
and sandstone. The clay shale and claystone may be expansive. Shrink - swell
potential is moderate.
With regard to geologic hazard the site is rated 4A on a scale of 1 to 7. It is
described as potentially unstao colluvium or bedrock on moder - slopes.
Emphasis should be on slope stability and orientation of beds both surface and
subsurface.
The area shows up on a U.S. Geological Survey report titled "MAP SHOWING
OUTSTANDING NATURAL AND HISTORIC LANDMARKS IN THE BOULDER - FORT COLLINS -
GREELEY AREA, FRONT RANGE URBAN CORRIDOR, COLORADO." 1975.
The report defines the immediate area as a naturally significant area:
"Some of the earliest collections of fossil mollusks of the Upper Cretaceous
Pierre Shale were taken here in the 19th century. Fossils occur chiefly ill
calcareous concretions in the Larimer Sandstone Member of the Pierre Shale
whose outcrop has a south - southwestward trend through the common corner of
sections 1, 2, 11, 12, Township 6 North, Range 69 West, which is just south of
the U.S. 287 bridge over Fossil Creek.
WHAT DOES ALL OF THIS MEAN?
This does raise another question about the suitability of this site for
the proposed development.
It should be noted however that the most dominate outcroppings of the formation
occur along the southern portion of the high part of the property, just above
the Fossil Creek floodplain, and also south of Fossil Creek - they are not
currently exposed to a large degree on the Pace site (this is the formation
that is perching the water table and creating the wetlands).
I am not a geologist. The developer should employ a geologist to assure that
design of the project is appropriate to deal with the potential geologic hazard.
Also, the geologist should give an opinion of the significance of the fossil
deposits on site.
This issue reinforces the fact that there may be areas within the community,
which because of their natural resource, natural history, and scenic nature,
hold special values as open space. If we can locate these areas well in advance
of development pressures and rising property values, and work with open space
funds to acquire them, we will end up with more quality in our parks and open
space, and will avoid confrontational situations with neighbors and
developers.
End of Item 40.