HomeMy WebLinkAboutPC94007 9-24-90 5401 69th AveMEMORANDUM
TO: File Re: Maranatha Residence Inc.
5415 69th Avenue North
FROM: Sy Knapp
Director JPublic Works
DATE: September 24, 1990
RE: Drainage Problem at Maranatha
and at Pebble Creek Apartments
Meeting Held September 5, 1990
History
Since construction of the addition to Maranatha in 1987-88, the City has
received several reports from "Sheila," the resident manager at Pebble Creek,
regarding drainage problems which they allege were caused by the construction
at Maranatha. Problems reported included both "flooding" problems and
"standing water" problems (i.e. - general nuisance, foul smells and
mosquitoes) and concern regarding possible "floatation" of their swimming pool
when they empty it for routine maintenance.
The Engineering staff conducted a survey of existing conditions on May 1,
1990, and found that the "bottom -of -the -ditch" grade between Maranatha and
Pebble Creek is substantially higher than the invert of culvert which comes
from Pebble Creek and higher than the City's storm sewer which drains into the
south end of this ditch (see survey profile).
Based on these findings, Sy Knapp had advised Clay Larson, Building Official,
to retain the performance bond which the contractor had posted in conjunction
with the site development permit until this drainage matter is resolved.
Knapp had also recommended lowering the entire ditch bottom to approximate
elevation 857.7. No progress had been made on this issue to date, with
everyone disclaiming responsibility. Recently, Larry Peterson, as the new
manager for Maranatha, has attempted to develop a resolution of this matter.
He organized this meeting for that purpose.
September 5. 1990 Meeting Summary
Larry Peterson, the current manager for Maranatha, organized this meeting to
"get things out on the table ...."
The following people attended the meeting:
for Maranatha: Larry Peterson, "Joan" and "Cliff"
for Wotterstorff Architects: "Dave"
for Sanders & Associates (Landscape Architects): "Bill"
for Barr Engineering: Dean Skallman
for Bolton & Menk (as successors to Suburban Engineering): Gary Harris
for Keller Construction: "Bob"
for City of Brooklyn Center: Sy Knapp, Director of Public Works
Larry Peterson briefly described the existing problems and showed pictures
showing flooding of the low areas in both parking lots. Joan and Cliff
confirmed that water frequently floods these areas, noting that while they are
flooded, the culvert under 69th Avenue is not flowing full. All agreed that
these areas remain flooded for 3 to 4 hours after rains, several times each
year.
Dean Skallman noted that the culvert under 69th Avenue was installed in 1977
by HCDOT, and that the low spot in the driveway west of Maranatha is at
859.25, while the top of the culvert is at approximately 861. Accordingly,
the driveway will start to flood before the water rises to the top of the
culvert under 69th Avenue. He noted that this information was contained in
his letter dated June 11, 1987. He also noted that his recommendation (see
his letter dated June 11, 1987) called for a 2-foot wide ditch bottom, with
2:1 slopes, with an invert elevation of 858.3 from 69th Avenue to the pipe
which drains Maranatha's new holding pond. He also noted that the plans show
compensating storage of 0.20 acre/feet. He also stated that he did not
calculate the flow capacity of this ditch on a "before" and "after" basis, but
believes that the flow capacity has not been reduced by the 1987-88
construction.
Sy Knapp challenged Skallman's assumption, noting that the "before" condition
provided a substantial ponding effect which he believes held the flood levels
down lower than the current conditions.
Skallman disagreed with this evaluation, stating that, in his opinion, the
construction has had an insignificant impact on the ability of the watercourse
to carry water.
Knapp noted that he believes much of the problem occurred because a number of
important items of information were not included in the plan development
process. This includes the following:
o No study of the watershed area which is drained through this
watercourse, i.e. - drainage area served, flow rates, etc.).
o The accuracy of the "before" topog and contours is very suspect. It
doesn't show the elevation of the lowest part of the watercourse (below
the 859 contour).
o Items not shown on the "before" topog map include:
- the culvert under 69th Avenue - and its size and elevation
- the culvert from Pebble Creek, and its size and elevation
the size and elevation of the City's storm sewer
Knapp stated that it appears that the Watershed Commission requirements have
been complied with. However, it appears that no one reviewed the project from
the perspective of assuring that it would not increase upstream flooding
problems.
Several times during the meeting, Knapp asked if the primary problem was (1)
the standing water problem or (2) the flooding problem, noting that the
resolution of the standing water problem would be relatively easy (i.e. - the
proposed lowering of the ditch bottom), while resolution of the flooding
problem would be much more difficult. The consensus appeared to be that both
problems needed to be resolved.
Knapp then advised that, since there seems to be a major concern regarding
"the flooding problem," he desired to review this matter in more detail with
J. M. Montgomery, the consulting engineers for the Shingle Creek Watershed,
and specifically, to get a second opinion from them as to whether the capacity
of the watercourse through the Maranatha property has been reduced by
Maranatha's construction.
The meeting adjourned, with an agreement "to stay in touch" with a goal of
correcting at least the standing water problem this fall.
cc: Larry Peterson, Maranatha
Clay Larson, Building Official
MEMORANDUM
TO: File Re: Maranatha Residence Inc.
5415 - 69th Avenue North
FROM: Sy Knapp
Director of �ublic Works
DATE: September 24, 1990
RE: Meeting held 9/21/90
Larry Peterson, manager for Maranatha, organized this meeting as a follow-up to
a meeting held on 9/05/90, and after telephone discussions with representatives
of Pebblecreek, and with Sy Knapp.
The following people attended this meeting:
for Maranatha - Larry Peterson
for Pebblecreek - Jan Susse and Sharon Shultz (Managers from the Metes and
Bounds Management Company)
Peterson asked Susse and Shultz to describe the conditions "before" and after
the 1987-88 Maranatha project.
Susse noted the following:
o drainage through this area has always been a problem because "everything
is flat "
o Pebblecreek was constructed in 1972
o when Susse started managing Pebblecreek in 1978, he spent a great deal
of time improving the flowage through Pebblecreek, installing "plastic
and rock" along the water course.
o prior to the 1987-88 Maranatha project, there was a definite ditch "with
rock and plastic" between Maranatha and Pebblecreek. Also, there was a
ridge, several feet high, along the east side of that ditch. That
ridge and the vegetation served to screen some of the debris that had
been dumped in Maranatha's wetland.
o Susse stated they had corresponded with Brooklyn Park and Brooklyn
Center in the early 1980's regarding the drainage problem and regarding
cleanup. Brooklyn Park's inspector Jim Demering attempted to help them
resolve those problems, but with limited success.
o "the culvert under 69th Avenue is too high . . " (also noting that he
has heard that engineers had operated from a wrong elevation).
Knapp asked Susse and Schultz whether, in their opinion, the primary problem was
(1) the standing water problem or (2) the flooding problem. Susse and Schultz
stated the primary concern is the standing water problem, noting that "we don't
have a serious problem with flooding." Peterson agreed with this, stating that
he believes Maranatha doesn't have a serious- problem with flooding.
Susse and Schultz stated they would be happy to cooperate with Maranatha to
resolve the problem.
Following the meeting with Susse and Schultz, Peterson and Knapp met to discuss
the status of the issues. Following are the items agreed upon:
o the primary issue now is the standing water problem rather than any
flooding problems.
o to resolve the standing water problem, it will be necessary to drain
water from Pebblecreek and from the City's storm sewer, at least down to
the invert elevation of the 69th Avenue culvert.
o the preferred way to accomplish the required drainage is to lower the
bottom -of -ditch grade to approximately 858.0. However, two factors may
make this difficult or impossible to do, i.e.: (1) concern regarding
exposing the footings under Maranatha's garage to freezing and (2) there's
a telephone line; and possibly other utilities buried along the west side
of the ditch.
o Knapp will have the City Engineering staff check out the utilities and
evaluate the feasibility and cost involved in moving them; then advise
Peterson of his findings.
o Peterson will then evaluate Maranatha's ability to proceed with the
work. He has a contractor's proposal to do the work for less than $2000
(not including utility relocation, etc, and assuming no special work
needs to be done to protect the garage footings).
o If it becomes impossible or impractical to lower the ditch because of
the factors noted above, or for other reasons, alternative plans will be
discussed.
cc: Larry Peterson, Maranatha
Clay Larson, City Building Inspector