Jump Creek Groundwater Recommendation Letter from Site Consulting, LLCSITE
CONSULTING, LLC
Mr. Shawn Brownlee November 18, 2014
Trilogy Development Page 1 of 3
2358 South Titanium Place 14046 -lettere
Meridian, Idaho 83642
Re: Groundwater Recommendation
Jump Creek Subdivision
NW Corner Blackcat & McMillan Roads
Meridian, Idaho
Dear Shawn:
As per your request, I have prepared the attached "Recommendations for Homebuilders" and
"Comments to Homeowners". These documents are intended to inform these parties of their
responsibility to construct and / or maintain homes that are free of water in the crawlspace. I have
forwarded this to Bailey Engineering for review and comment. These are stand alone documents
intended to be issued without cover letter. We appreciate this opportunity to be of service. Should
you have any questions or require additional information, please contact our office at your
convenience.
Respectfully
Bob J. Arnolc
cc: Bailey Engineering
208-440-6276 ' bjarnoldpe@msn.com ` Post Office Box 190537 Boise, Idaho 83719
SITE
ONSULTING, LLC
RECOMMENDATIONS FOR HOMEBUILDERS
Jump Creek Subdivision
November - 2014
• Bearing pressures of up to 1500 psf are available for foundation design.
• After crawlspace excavation, inspection by a qualified soils engineer is recommended to
approve foundation support soils.
• Installation of at least two vertical drains in opposite corners of the crawlspace is
recommended. Vertical drain is a small excavation or boring of at least two square feet that
extends five feet below the foundation and is back filled with drain rock.
• It is recommended that the construction joint between the footing and the stem wall be sealed
with asphalt -based sealer.
• The trench beneath foundations, where utilities pass under the footing, must be properly
backfilled with soil or bentonite to prevent water from entering the crawlspace by way of utility
trenches.
• Soils containing fat clay or frozen clods or chunks are not recommended for backfill. The use
of these materials may result in voids or flow paths allowing surface water to enter the
crawlspace.
• Low-density foundation and utility trench backfill has been shown to be a major contributing
factor to water accumulating in crawlspaces throughout the Treasure Valley. Homebuilders
are encouraged to properly backfill all foundations and all utility trenches in accordance with
local building code requirements. This is especially critical on lots where bedrock, cemented
soils, and compacted fills are present below the foundation.
• Foundation elevation and site grading must promote drainage away from the foundation.
Unless the local code is more stringent, a minimum of FIVE percent slope for the first ten feet
from the residence is required.
• Crawlspace vents are to be above finished adjacent subgrade.
• Complete roof gutters are recommended with down spouts directed away from foundations
and not on to foundation backfill soils.
• Landscaping should be designed to promote drainage away from foundations.
• Flowerbeds and landscaped areas must be designed such that irrigation water and roof runoff
is not retained against foundations.
• Proper design and maintenance of sprinkler systems is required. Excessive watering may
lead to water entering the crawl space. Lawn area sprinklers should not spray toward
foundations or cause water to accumulate near foundations.
• Side lots between houses must provide for adequate drainage of both lots. Fences and
borders should not restrict the overland flow of storm runoff.
• This subdivision is located within the Treasure (Boise) Valley of Southwestern Idaho. This is
a high desert region with minimal annual rainfall, (< 13"/year). The proper selection of
grasses, bushes, and trees that thrive in such conditions will also prevent over application of
irrigation water.
NOTHING FOLLOWS
208-440-6276 * bjarnoldpe@msn.com " Post Office Box 190537 * Boise, Idaho 83719
SITE
ONSULTING, LLC
COMMENTS TO HOMEOWNERS
Jump Creek Subdivision
November - 2014
• Foundation elevation and site grading have been constructed to promote drainage away
from the foundation. Final, completed lot grading must promote drainage away from the
foundation. Modification of the grading near the residence may result in water entering
the crawlspace.
• Roof gutters with down spouts have been or should be installed that direct storm water
away from foundations and not on to foundation backfill soils. Modification of downspouts
is not advisable without a plan to move storm water away from the foundation.
• This subdivision is located within the Treasure (Boise) Valley of Southwestern Idaho.
This is a high desert region with minimal annual rainfall. The proper selection of grasses,
bushes, and trees that thrive in such conditions will also prevent over application of
irrigation water.
• Landscaping should be designed to promote drainage away from foundations.
Flowerbeds and landscaped areas must be designed such that irrigation water and roof
runoff is not retained against foundations.
• Proper design, maintenance and scheduling of sprinkler systems are required. Excessive
watering is the largest source for water in local crawl spaces or basements. Sprinklers
should not spray toward foundations or cause water to accumulate near foundations.
Over application of irrigation water is the single largest factor contributing to water
accumulating in crawlspaces. After occupancy, the settings for any automatic sprinkler
system should be reviewed and adjusted to apply the minimum amount of water required
for landscaping maintenance. It is recommended that the local water company or a lawn
care expert be consulted about the amount of water required.
• Runoff or drainage to adjacent property is not allowed without developer approval.
NOTHING FOLLOWS
208-440-6276 ' bjarnoldpe@msn.com " Post Office Box 190537 ` Boise, Idaho 83719