PERMFILE41630

• Permit No: M2005045
• IBM Index Class Name: Permit File
• Doc Date: 4/7/2006
• Doc Name: Proposed Detention Pond
• From: Matt Carnahan
• To: DMG
• Media Type: D
• Archive: No

Detail of the access road/ Run-on diversion ditch crossing is described in the
attached Prymorys letter.
3. Detention Pond Construction Specifications
a) The earthen material proposed for construction is classified as
an AASHTO type A-7 soil (Arboles). The following table
describes some physical properties of this soil type including
particle size gradation parameters:
Soil t e Cla Permeabilit Percent assin sieve size mm) Li uid limit Plasticit index
Pct In/In 4.750 2.000 0.425 0.075 Pct
A-7 40-55 0.06 - 0.2 95-100 95-100 90-100 80-95 45 - 60 20-30
bj Earthen material used for construction of the detention pond
dam structure shall be compacted to a dry density of not less than
95% of maximum dry density within an optimum moisture range
of+/- 2% as determined in accordance with ASTM D1557.
c) Earthen material shall be placed in vertical lifts not to exceed 8
inches (uneompacted).
d) Based on the spillway discharge flow design velocity, gabions
used in the spillway and inlet structures shall meet an ASTM Type
VL gradation classification as follows:
Gabions Ty e VL Max. Dimensions (m) % Smaller K,„
0.30 100
0.25 50-70
0.15 30-55 0.15
0.08 10
e) All armoring will be constructed using gabions as described
herein.
f) Gabions shall be within the following physical property ranges:
Specific Gravity (ASTM C127) 2.65
Abrasion Resistance (ASTM C535) 50% max.
Soundness Loss (ASTM C88) 20% max.
g) Quality Assurance Plan: All earthen material and gabions to be
used in the construction of the detention pond shall be shown
through ASTM laboratory test results referenced above to meet or
exceed such specifications before placement.