SWM Questions to City:
February 02, 2006
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February 2, 2006
To: Marylou Berg, Assistant to the City Manager, Rockville
From: Mark Pierzchala, President, College Gardens Civic Association
Here are the questions from the CGCA to City staff concerning a Storm Water
Management facility in the College Gardens Watershed. These come from many
different people, most recently, over a 6-week period, but also over several
years.
1. What is the minimum amount of water the City would consider controlling
with a SWM facility in the College Gardens Park in terms of acre-feet of water?
This gives the community a way of judging the minimal impact on the park.
2. Any SWM facility in the park would seem to not address much of the storm
water in the College Gardens Watershed. This would include storm water from
Auburn Avenue, Baylor Avenue, College Parkway, Clemson Court, parts of Princeton
Place, and even some from Plymouth Woods. Isn’t the location of the
proposed SWM facility too far up in the watershed to be effective?
a. What percent of the storm water in the College Gardens Watershed would be treated by the SWM facility?
b. The purpose of any SWM facility in the park would be to mitigate water coming out of the pipe outlet just west of Princeton Place. What percent of the water coming out of that pipe outlet comes from the pipe that runs under the College Gardens Park? What percent of this water comes from the other pipes that feed into this pipe outlet? Have these percents ever been measured?c. It appears that, at most, only about 50% of the water coming out of the pipe would be affected by a SWM facility in the park. While this would be an improvement, it would not in the end stop the kind of destruction to the streambed that we have seen. So why bother? It appears that the City would still have to treat the banks of the College Gardens Tributary.
3. It appears that the vast majority of the water that would be treated by
a SWM facility in the College Gardens Park would come from commercial or institutional
property such as apartment buildings. What is the quality of the water that
would be coming from these parking lots? One of the parking lots hosts a fleet
of service trucks. Won’t storm water from these sources deposit a lot
of dangerous chemicals into the ponds in the College Gardens Park? Has the
City ever measured the quality of the water coming through the pipe that runs
under College Gardens Park? What is the use of eliminating pollutants to the
stream if they end up in College Gardens Park?
4. There is a pond on the Comcast property (West Gude Office Park). Is it an up-to-date SWM facility? Does it hold back storm water or reduce pollutants? If so how much?
a. What has the City done, if anything, to talk to the owners of that property to get them to make the pond into a modern SWM facility?
b. If the Comcast pond is retrofitted to be a modern SWM facility, would it be able to handle adequately the ‘quality’ part of SWM, in addition to helping with quantity? Would it be able to filter dangerous chemicals before such water would get to a pond in College Gardens Park?
c. We understand that there is no way to force a private property to handle storm water until there is major reconstruction needed. On the other hand there can be negotiations and incentives such as property tax breaks that could be tried to get such private properties to help out the community. Has any of this been tried?
5. The Celera property would contribute to the storm water handled by a SWM
facility in College Gardens Park.
a. Has the City talked to the owners of this property to convince them to handle storm water on their own property, for example through negotiations and incentives including property tax incentives?
b. Has the City considered pumping this Celera water to the existing SWM facilities in King Farm? These facilities are very large and could handle this additional amount of water.
6. If the College Gardens area were in its natural state, SWM would be taken
care of through groundwater recharge because the area would be almost totally
pervious. Why aren’t techniques to recharge groundwater considered as
part of the City’s bag of tricks for SWM?
a. Has the City ever tried groundwater recharge?
b. What kind of volume could this technique handle?
c. A resident suggested that water from the new school could be directed underground to recharge groundwater and feed into the pond through natural springs that used to feed the pond before all the buildup. What would it take to study this possibility?
7. If a SWM facility is put in College Gardens Park, how do we know that future
building upstream would not increase the amount of water that has to be handled
by such a facility? How do we know the quality of water coming into such a
facility would not be worse in the future?
8. How much maintenance has been deferred at the park because of City plans
to put in a SWM facility in the park? Especially for the pond; shouldn’t
this be mucked out on occasion according to a regular schedule?
9. Would it be possible to engineer a SWM facility in College Gardens Park
that would handle only the runoff from College Gardens? That is, storm water
from Yale Place, Yale Village, and the school?
10. Mosquitoes:
a. Any SWM solution would result in more surface area than the current College Gardens pond. What will be the increase in mosquito population?
b. How would an increase in mosquito population be mitigated?
c. Have there been mosquito problems at other SWM facilities in the City? If so, why and where?
11. In the past decade, how many rain events exceeded the design capacity
of such a pond? To answer this, use the capacity and design of the proposed
College Gardens Park SWM pond from several years ago.
12. Concerning the 54” pipe, would an opening in the park for pipe this
huge be a safe thing to do? It is more than a matter of hiding it. How are
you going to keep kids out of it?
a. What about the force of energy coming out of the pipe during a large storm. Isn’t this a bit much for a smallish park and the kids who play in it?
13. Please summarize City quantitative goals for SWM and how these apply to
the College Gardens situation. What measures are used? Does the City ever
measure the benefit of its SWM facilities? Is compliance with state and federal
requirements based on direct measurements of benefit or on other bases?
14. Which laws force the City to implement SWM facilities?
15. What is the role of the Army Corps of Engineers?
a. One technical possibility for a SWM pond is an in-stream solution at the end of the pipe outlet feeding into the College Gardens Tributary. Apparently the Army Corps of Engineers says this is not a possibility due to an alternative location for such a facility that is the park. However, this is not a full alternative and it would dump pollutants into the park. Has the City tried formally, shoulder to shoulder with the College Gardens Civic Association, to request a waiver to their rules?
16. Is the effort to implement a SWM facility in College Gardens related to
state and federal requirements or to voluntary goals by the City of Rockville?
17. Isn’t College Gardens being picked on because the City has no other
place to put such a facility?
18. What is the City plan for SWM in areas where a park is not available?
After all these SWM facilities go in, what percent of the city area will be
under control?
19. What will the City do if something goes wrong with the SWM facility? How
quickly and to what extent will the City ameliorate any problem?