Thursday, May 31, 2018

Does it make sense to rebuild Main Street Ellicott City?

After the shock of a second disaster in as many years wiping out small businesses all along both sides of Main Street, the question whether to rebuild at all is asked with new urgency.

The answers to this fundamental question vary with distance from the disaster. Interestingly, the desire to rebuild right away is inverse to the distance. Those directly affected in their livelihood are much more likely to roll up the sleeves and rebuild than the armchair commenters on the Washington Post website such as pragmaticoneThey’re going to rebuild the infrastructure? Why?! This is clearly a case where we need to accept that floods are becoming more frequent, and move residences and businesses out of the floodplain. Stop wasting taxpayer dollars rebuilding areas that are destined to be destroyed by climate change.  bulldog501 is more drastic: Tear down the town and make a park. There are also opportunities for political digs such as the one from dcguy00Maybe developers need to be dealing with stormwater management on site, rather than letting more water flow off of hard surfaces. I believe Hogan referred to this as a rain tax.
A fairly wide stream bed meets this tiny culvert at Ellicott Mills Drive.
Disaster is inevitable. (Photo Philipsen, 10/2016)

Many shop-owners and restaurant operators, by contrast,  express that giving up is not an option, even though their spirit is low after having been clobbered twice in such short order. “We own that building. Walking away from our structurally sound building is not an option.” (Angie Tersiguel, quoted in the WP).

There are also merchants who have already decided not to rebuild:
“I am definitely not rebuilding,I’m not going back there. Not at all. Nothing has been done to fix or alleviate the problem, so I don’t have any reason to move back down there. You didn’t protect the people there. You basically put them in harm’s way and rolled the dice that there wouldn’t be another flood.” Jereme Scott, Cotton Duck Apparels (SUN)
A fairly reasonable position between these two extremes is to "only rebuild after protections are in place". But this is not as obvious as it sounds and it wasn't the position many people took after the last flood. Rob Brennan, an architect with an office on Main Street, who is currently forced to work from temporary quarters, is a member of the masterplan Community Advisory Group (CAG) that had been appointed to accompany the watershed masterplanning process that started late last year and was supposed to be completed this month. The Advisory Committee like most thought there would be enough time to do a thorough comprehensive planning process in which infrastructure, place-making, open space and flood control were integrated elements. A laudable approach, except it takes too much time. The final presentation, planned for the week before disaster struck, was postponed by the Planning Department because the department deemed the plans not yet developed enough, Brennan told me. (Masterplan Design team)
From the March 2018 version of the masterplan presentation

The draft plans considered several large scale solutions for retention and conveyance, the pair of terms everyone had to learn who was interested in neutralizing the the copious amounts of water from downpours, such as the most recent one. Those measures take years to design and construct, even if the $84 million dollars quoted for realizing some suggested measures were readily available.

What should merchants and restaurateurs do during such a long unprotected period? How would their structures and buildings not fall into irreversible decay? Brennan said that even the weeks it took in 2016, before owners and tenants could begin reconstruction, cost significant extra money for "remediation" such as mold control. Water intensifies its damage when it is allowed to fester. Back then, reasonably enough, public safety, access and infrastructure concerns were addressed before private construction could begin.
Early reconstruction of stream walls with granite seem to have withstood the
impact of 2018 but couldn't contain the water. (Photo: Philipsen 10/2016)

Can the urgent need for protective measures be addressed in months  not years? Can obstructions be reduced, conveyances increased, and retention be created in a short enough time that rebuilt businesses will have the peace of mind that comes from protection that is completed concurrently? An assurance that the destructive force of water would be mitigated to such an extent that small individual fortifications of properties stand a chance to survive the next extreme rainfall would go a long way to motivate reconstruction. But the Executive has not provided any such assurance. He only said "you have tough choices to make". He will have to, as well, one may want to add. 

In October of 2016 road repairs and infrastructure recovery after the August flood was in full swing but main Street was still pretty much a ghost town. Businesses had been kept at bay for months. This time, with damage to public infrastructure less intensive, it is urgent to find a way in which public works repairs and private construction can operate side by side, even if that creates some logistical headaches and poses some risks.
How the stream re-emerges south of Main from under the restaurant
La Paloma (Photo: Philipsen 10/2016)

In spite of all the talk about supporting the town, Brennan says that business owners and residents received most of the money from insurance, the local Ellicott City Partnership and private donations after the 2016 flood. There wasn't a big County bond taken up nor was there extensive State money coming to private owners. No immediate large scale projects were considered. The SUN reports that FEMA paid out $4.9 million in flood insurance to 27 policy holders and that FEMA had provided another $7million in disaster assistance.

This time County and State need to provide emergency funds large enough to do the heavy lift which is needed for resilient reconstruction on the private and the public side. To ensure that no more good money is lost as in the last reconstruction (at least on the private side),  stipulations and requirements must be tacked to permits for resilient reconstruction. Flimsy historic wooden storefronts won't keep nature out. Posts and glass need to be reinforced without destroying the historic character. Howard County should provide the services of experts who can advise on resilient but attractive reconstruction, both, for private and  public projects and public funds should cover the extra cost as an investment into the future.
Each star a "pinchpoint" where water jumps the channel (March 2018 prsntn)

Howard County can't continue with sidewalks that get washed away and water undercutting the adjacent buildings. The County can't continue without an emergency preparedness plan in which agencies, businesses and visitors and residents know exactly what to do. It can't go on that residents, customers, visitors and merchants get caught in flood-waters relying on dangerous rescue. It can't go on that cars remain in the danger zone in spite of an official flash flood warning and then get washed away so that 198 wrecks clog up the precious drainage capabilities.

In the hollers of Southwest Virginia police finds the resources to drive into the valleys and warn residents via loudspeaker to seek higher ground when there is an imminent meteorological menace as they did just about the same time this recent   storm hit Ellicott City. (The meteorological area of instability was that large!). In Baltimore's Mt Washington the customers of Whole Foods and surrounding businesses evacuate every time the Jones Falls threatens to crest and the business owners close the flood gates of the protective walls around their property, a procedure that has worked well for years.

destroyed stream walls had been rebuilt
(Philipsen 10/2016)
The major pinch-points that were highlighted in the plans of the watershed consultant team, need to be removed with the highest priority. Culvert enlargements under streets and buildings are complicated. Brennan said a redesign for the most egregious pinch at Ellicott Mills Drive had already been done and construction was supposed to have begun later this year.

Maybe now the pathway can be realigned. The flood itself showed how the water wants to go. The point where a reasonably large stream bed running alongside upper Main Street turns into a tiny culvert just west of Ellicott Mills Drive was the site of major damage in both recent floods. The first time, water jumping up to Main Street, took out an entire hillside undercutting the St Luke African Methodist Episcopal Church. This time nature simply blew out all of the obstructing Ellicott Mills Drive roadbed and the first courthouse and jail building right with it.

As far as one can surmise from the evidence, the water breaking through Ellicott Mills Drive then expanded into lot F, one of the areas suggested as a water retention area. Would there be a way to make the lot a retention facility without millions of dollars for an underground storage tank with a park and structured garage on top or without losing it as a parking lot during normal times?

Could the existing lot become a designated retention basin by surrounding it with a wall that has a designated overflow and could maybe hold the initial 5-6' feet of water on its about 1.2 acre size? (In the current configuration the lots flood to about 2'-0"). Flood gates woulds allow for driving and walking in and out and be closed when water starts flowing in. Flash flood warnings would trigger an evacuation of the lot similar to what happens at the Whole Foods in Mt Washington. Additional water then would have to be be safely conveyed through the second set of culverts under Main Street, located west of the brew pub and under Palapia, to get to lot D south of Main Street. (A bypass is one of the proposed conveyance strategies of the draft plan). That parking lot behind the post office could become another even larger retention area.
Cost (3/2018 Presentation)

Again, instead of the long-term strategy of replacing surface parking with structures and building huge underground storage, the idea would be a short-term surface solution with a wall around the lot to hold water in an emergency. Not the prettiest thing, but also not really in conflict with the historic district itself and probably not more unsightly than a sea of parked cars is in the first place.
buildings straddle the stream low, restricting flow (Philipsen 10/2016)

Lastly, since its seems impossible to hold or convey enough water in those initial steps, it should be investigated whether Main Street itself could become a safe conduit. (This is not included in any of the options in the draft plan).

Removable flood barriers erected on both sidewalks could  protect the stores from the impact of rushing water and debris. There exist various modular solutions that have been tested elsewhere.

Those relatively light- weight Jersey barrier type, interlocking elements have been made for quick installation after a flood warning and have been successfully installed, for example in low lying areas of San Francisco's Mission District. 

Looking at photos of those barriers and then the videos of  the rushing walls of water racing down Main Street would elicit obvious doubt if those walls would hold. They would probably only work if the volume of water has been reduced enough through significant retention measures. Maybe then the water in the street would not be higher than the barriers as the hydraulic modeling of the updated hydraulic study suggests. 
Temporary flood barriers at Folsom and 19th Street in the Mission District
of San Francisco: DPW at the ready 24/7
Obviously, the 100 years between 6" floods are not available. The "logic" that a second or third event of such extraordinary might is less likely because one event just happened is faulty, even within the traditional definitions of the 100 year event model which calculates precipitation over 24 hours, not 2 or 3 hours.  Statistics don't work that way, the odds are always the same, whether one subscribes to the 100 year flood model or not. Whether the risk is one in a 100,  one in 500 or one in 10 doesn't matter, the risk remains the same every day, no matter that two floods just occurred.

The principally laudable approach of comprehensive masterplan effort in which resiliency doubles up as good urban design and urban programming and which is discussed in many public meetings needs to be re-thought in favor of a much more direct approach with a strict timeline.
Swedish model flood protection element

Nothing, though, can be done without money. Instead of dribbling little funds into half baked measures, Ellicott City has become a case of all or nothing that should be of regional interest.

Big or not at all was also the choice for Ron Young, Mayor of Frederick in the 1990s, when he decided that a large  underground water conduit of four 20x20' culverts all around downtown was the only way to really save Frederick from re-occurring debilitating floods such as the one of 1976. The City not only constructed the entire Carroll Creek flood mitigation system but got its money back through a booming downtown that exceeded even the most daring dreams Ron Young and his team ever had. Just two weeks before Ellicott City flooded again, Frederick received 6" of rain in two hours. It withstood this calamity with only minor flooding in the streets.

Certainly, conditions in Ellicott City are not comparable, but here half measures will do even less. Creative out of the box solutions are needed, at least for the immediate protection needs. If none of those quicker solution work, or if there is no money for them, rebuilding just makes no sense.

Even the March masterplan considered partial abandonment since the proposed retention and conveyance strategies show more promise for upper Main Street and less for lower Main Street. In the March presentation it was stated:
Over the long-term, if any buildings proved too difficult to flood-proof and be habitable (at least on the first floor, these structures may be repurposed to allow water to flow through and serve as "releif points". The structure itself could be preserved to maintain the historic architectural integrity of Main Street. (March 18 presentation)
The wettest April and May in decades (US East Coast) sheds a bright light on the mundane science of stormwater management. And with it comes the question if habitation can be maintained in all those locations that were historically settled. As hard as it is, without a huge and costly lift, the answer may well be: No.

Klaus Philipsen, FAIA
Corrected misspellings of Angie Tersiguel's and Jereme Scott's name in the initial version. My apologies!

May 2018 Progress to Date overview by Howard County Planning
2016 Hydrology Study (June 2017 update)

See also on this blog:
When history repeats itself 20/20 hindsight must become foresight

Water had washed away  side-yards when the underground culvert was full (Philipsen, 2016)

Caplan has started reconstruction, many other buildings were still boarded in the fall of 2016  (Philipsen, 2016)
These rocks had to save the church in 2016 and stayed in place in this flood (Philipsen, 2016)

The Hudson/Tiber stream channel south of Main Street in a more "natural" segment behind the buildings (Philipsen, 2016)
Another tributary, the New Cut  Branch "t-bones" the Hudson/Tiber stream behind buildings bringing additional waters to an
already overwhelmed channel. An upstream retention basin is part of the draft plan proposal

Structures and streams are forming an entity in Ellicott City: reconstruction of a building corner (Philipsen, 2016)

buildings straddle the stream low, restricting flow (Philipsen 10/2016)

buildings straddle the stream low, restricting flow (Philipsen 10/2016)

At the foot of Main Street only a narrow channel allows water to reach the Patapsco (Philipsen 10/2016)

In defiance this remnant of the clock had been re-installed after it had been retrieved downstream
(Philipsen 10/2016)

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