HomeMy WebLinkAboutOGARD S12643Onsite File
July 5, 2023
PO BOX 240773
ANCHORAGE, AK 99524
522-7773
677-7766 (FAX)
FORGECIYIL.COM
MOA Development Services, On -Site Water & Wastewater Program
4700 Elmore Rd
Anchorage, AK 99507
Subject: Proposed Ogard Subdivision, Lots 1 & 2
S12643 - Septic feasibility
Dear On -Site Services Engineer:
A petition has been submitted to subdivide two existing lots, adjusting the lot lines and forming
the new Ogard Subdivision_ We our presenting our findings that each new lot will have sufficient
area and potential for on-site wells and septic systems.
The property in general is moderately sloped up away from Wesleyan Avenue to a flatter area with
existing buildings. There are some relatively steeper areas with grades ranging from 5% up to
around 25%, with just a few short drop-offs where slopes are approach 45%. There are no
significant portions where slopes are greater than that. Both properties are greater than 40,000 SF
in size.
Proposed Lot 1 has an existing well and permitted septic system on it, with an alternate site.
On 6/26/23, a test hole was dug on proposed Lot 2 in an area that seemed appropriate for septic
systems, based on the vegetation and topography. A monitoring tube was place in the test hole and
groundwater checked on 7/3/23, 7 days after the excavation. The test hole was dug to 15' deep.
The soil was very uniform. consisting mostly of sandy gravel (GM). A percolation bench was
excavated approximately 4' below grade. The result was a percolation rate of under 1 min/in. A
future septic system will likely need a sand filter to slow absorption, but the soils will definitely
support a septic system. The attached septic feasibility plan shows the required 10,000 SF of
reserve area set aside.
Although the groundwater monitoring was not done during the months when, historically, the
water is at its highest, we are confident that the lack of groundwater discovered is typical of the
area. Groundwater levels will be recorded again during the seasonal high in October.
As the number of properties has remained the same, the number of possible wells has not increased,
and so there is no additional water demand from the aquifer. The existing well on Lot 1 does not
have a well log, but the pump log shows that it is at least 100' deep, and it produces enough water
for the single-family home on that lot. A future well for Lot 2 would reasonably expect to be 100'
deep and produce a minimum of 1 GPM.
Based on our field studies, research, and water monitoring completed to date, it is clear that Lot 2
of the proposed subdivision is capable of supporting a new well and onsite septic system.
Sincerely,
Benjamin Schiller, PE
Benja%,,Schiller
% CE 12592
7/5/23• . •�c���
1
i�
it
EXISTING
PERMITTED SEPTIC
SYSTEM
ADJACENT'
PROPERTY ON CITY
WATER
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Benja i Schiller / 0
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5/24123
ll` ROFESSION .e.
OGARD SUB. LOTS 1 & 2
SEPTIC FEASIBILITY PLAN
SEPTIC RESERVE AREAS
30
FEET t `�= 00
", 6.5.
EXISTING WELL
�f
-�T
i- FUTURE WELL
NGINlIRING
DEPTH
(feet)
1
2
3
4
7
8
9
1
1
1
1
1
1
1
1
1
1
SOILS LOG AND PERCOLATION TEST
ENGINEERING
LEGAL DESCRIPTION: PROPOSED OGARD SUB, LOT 2
PERFORMED FOR: ALTON OGARD
DATE: 6/26/23 PARCEL ID#: 006-324-19
TEST HOLE 1
•:
GM (SANDY GRAVEL)
NO WAS GROUND WATER ENCOUNTERED?
- IF YES @ WHAT DEPTH?
NONE DEPTH TO WATER AFTER MONITORING
7/3/21- DATE OF MONITORING
DATE
READING
START TIME
NET TIME
(MINUTES)
DEPTH To
WATER
NET DROP
(INCHES)
INCHES)
5/9/22
1
9:51
0:15
3
9
616
2
0:16
3
9
616
3
0:16
3
9
616
4
0:17
3
9
616
5
0:18
3
9
60
6
0:18
3
9
616
6" DIAMETER TEST HOLE PRESOAKED PRIOR TO TESTING
PERCOLATION RATE: 0.05 (MIN/INCH)
SITE PLAN
COMMENTS: USCS SOIL CLASSIFICATION WAS VISUALLY DETERMINED
TECHNICIAN: M JAKUBISIN