Reeder & Pols presentation to ANC 1C-Dec 3 2014

8/10/2019 Reeder & Pols presentation to ANC 1C-Dec 3 2014

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KALORAMA PARK

Presentation to ANC 1C

by

Belinda Reeder & Cynthia Pols

on the

Proposed DPR/DGSRe-design of the Plaza

Dec. 3, 2014


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DPR/DGSS PROPOSAL TO

DEMOLISH & REPLACEKALORAMA PARKS PLAZA:

THE ORIGINAL NATIONAL PARK

SERVICE DESIGN & WHY IT SHOULD

BE PRESERVED

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THE NATIONAL PARK

SERVICES 1947 PLANSFOR KALORAMA PARK

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Overall Plans

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Close-up of Plans for Plaza Area

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THE NATIONAL PARK SERVICE

CAREFULLY ADHERED TO THE 1947

PLANS AS IT BUILT THE PLAZA

SATELLITE VIEWS OF THE PLAZA OVER

THE YEARS SHOW THE SYMMETRY &

BALANCE OF THIS DESIGN & ITSCONSISTENCY WITH THE 1947 PLANS

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1999 Satellite View of the Plaza Area

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EXCEPT FOR THE INTERPLAY WITH

NATURE (THE LOSS OF TREES INTHE PLAZA & THE ADDITION OF

TREES IN THE PLAYGROUND), THE1947 DESIGN OF THE PLAZA & THE

OTHER ROOMS IN THE UPPER

AREA OF THE PARK HAS REMAINED

INTACT FOR SOME 50 - 60 YEARS

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WE SUDDENLY FIND OURSELVES FACED

WITH DPR/DGSS PROPOSAL TO

DEMOLISH THE PLAZA IN ITS ENTIRETY

& REPLACE IT WITH A NEW PLAZATHAT WILL NOT HAVE THE STRUCTURE

& SYMMETRY OF THE EXISTING PLAZA

AS ESTABLISHED BY THE 1947 NPSDESIGN

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DPR/DGS Final Redesign Plans (Nov

18, 2014)

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TO PUT THE DPR/DGS PROPOSED

CHANGES IN CONTEXT, IT IS HELPFULTO LOOK AT THE PLAZA IN VARIOUS

WEATHER CONDITIONS & SEASONS

NOTE THAT THE SYMMETRY &

BALANCE OF THE PLAZAS DESIGN

SHINE THROUGH REGARDLESS OF THE

CONDITIONS

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Aerial View of Plaza (winter of 2009)

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Aerial View of Plaza (2010)

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Aerial View of Plaza (early 2011)

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Aerial View of Plaza (spring of 2011)

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Aerial View of Plaza (summer of 2011)

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Aerial View of Plaza (July of 2014)

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IT IS ALSO IMPORTANT TO KEEP IN

MIND THAT THE PLAZA, IN ITS

CURRENT FORM, ACCOMMODATES AWIDE RANGE OF USES & ACTIVITIES &

IS MUCH MORE THAN AN EXTENSION

OF THE NEARBY PLAYGROUND

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People Using the Plaza (2005)

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People in the Plaza (2008?)

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People in the Plaza (2009)

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THE PLAZA, IN ITS CURRENT FORM,

PROVIDES A WONDERFUL PUBLIC

SPOT WHERE NATURE & DESIGNCOME TOGETHER IN HARMONY

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Hawthorn-Northeast Corner of Plaza

(fall of 1993)

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Hawthorn in Bloom in the Plaza

(undated)

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Hawthorn in Bloom in the Plaza

(undated)

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Eastern Side of Plaza (2008)

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Western Side of Plaza (p re-erosion)

(spring of 2003)

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Western Side of Plaza (pre-erosion)

(spring of 2003)

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View of Plaza from the Oval (2008?)

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View of Plaza in Winter (2009)

file:///.file/id=6571367.16file:///.file/id=6571

367.16042497041094

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DPR/DGS PROPOSAL FOR A

PERMEABLE PAVEMENT

SYSTEM FOR THE PLAZA:

QUESTIONS & CONCERNS ABOUT THE

VIABILITY OF THE PROPOSED SYSTEM

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The bad history of the 2009 anti-erosion

project requires extra vigilance

Following DPRs 2009 implementation of an anti-

erosion project, erosion worsened

That 2009 project involved tearing apart the parkto install 3 bioswales, modify 3 catch basins,

install 1 new catch basin, remove 2 catch basins,

& install a new play area for children

Some 5 years later, the 2009 project remains

unfinished & caused damage to the park in many

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The 2009 anti-erosion project did not includeimprovements or repairs to the trench drainsystem in the plaza The trench drain system had worked well for some 50

- 60 years It was damaged in recent years either by DPR

contractors for the 2009 anti-erosion project or bysome other occurrence like root intrusion

It has not been repaired in spite of its centralimportance

DGS confirmed in July of 2014 that the trench drainsmain drain pipe was damaged

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DPR commissioned a report in 2012 by anengineering firm (Volkert) to assess the 2009 anti-erosion project

Volkert found numerous flaws in theimplementation of the 2009 anti-erosion project,including that the 3 catch basins associated withthe bioswales were not working properly

DPR failed to develop proper contracts in 2009for the anti-erosion project or to oversee thecontractors

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The bad history of the 2009 anti-

erosion project requires extra vigilance

The fix proposed by DPR/DGS in 2014 for themess created by the 2009 anti-erosion project is acomplex, engineered permeable pavementsystem

Based on history, it is not wise to automaticallyassume that the planners have it right

Given history, it is reasonable to question

whether DPR/DGS will implement the aggressivemaintenance plan required to keep the proposedsystem in operation

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How the proposed permeable

pavement system would work

It captures & temporarily stores water in a stone

reservoir directly below the pavements surface

The system is designed to collect water & return

it to the stormwater system or filter it into thesoil within 48 hours

If working properly, it provides some control of

water run-off It can also slow down the speed at which surface

water is released into the stormwater system

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How the proposed permeable

pavement system would work

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What are key design issues as per


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DCs Stormwater Management

Guidebook (SWMG)? The below-surface drainage system for slowly

emptying the reservoir:

-This system may consist of: drainage pipes(over& under drainstypically 4 6 in diameter &

with 3/8 perforations); & the infiltration sump

or a second stone reservoir below the under drain

pipes

- Other factors: number of drainage pipes in the

reservoir; space between drainage pipes

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DCs Stormwater Management

Guidebook (SWMG)?

Connections to the stormwater system to

drain the water out of the reservoir

Geotextile & other walls between the stone

reservoir & adjacent areas to prevent clogging

of the pavement & drainage system

Distance from nearby buildings and utility

lines (DCs SWMG recommends at least 10)

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Possible problems with permeable

pavement systems?

The reservoir has insufficient storage capacity

Due to design deficiencies, the water retained

below the pavement surface in the reservoir

cannot drain within the requisite 48 hours

Some or all of the drains in the reservoir

become clogged over time

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Possible problems with permeable

pavement systems?

The surface pavements clog up over time,

blocking water from filtering into the reservoir

The geotextiles used to create walls betweenthe reservoir & nearby landscaped areas break

down over time, allowing soil to migrate into

the reservoir

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Main problems with a permeable

pavement system in the plaza area?

The soil beneath the plaza has limited ability toabsorb water:

- A DGS subcontractor found the soil to be close to not

permeableit can absorb only about inch of waterin 48 hours (0.005 inches/hour)

- The subsurface reservoir must be engineered to bothretain virtually all the water & to gradually release it

into the stormwater system over 48 hours- The stone reservoir must be deep (likely at least 4) &

equipped with multiple drains

- The system must be linked to the stormwater system52

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DGS tested the water infiltration rate at 8 points in

the park in July of 2014- The plaza testing points are shown on the map in

the next slide (B-2 is the main testing point forthe plaza; tests were also conducted at B-1)

-The results of the tests at all 8 points are shownin the slide after that

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Nearby areas drain into the plaza area (the roof of the reccenter, the 2 playgrounds, & the Oval), compounding theproblems associated with the soils limited permeability:- Additional issues are implicated by unformed plans to

reconstruct the adjacent playgrounds

-The surface of the adjacent playground already poses a threat toa permeable pavement systemit is 6 above the plaza &consists of mulch & similar loose materials

- DPR/DGS plans to upgrade the playgrounds but does not plan toinstall permeable surface (DGS Nov. 5 announcement)

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DPR/DGS plans to replace the existing surface with wood chips(likely incompatible with the proposed permeable pavementsystem as loose materials could clog the system)

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Main problems ith a permeable


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The plaza directly abuts the rec centerunder theSWMG, the 10-foot strip in front of the rec centershould not be part of the permeable pavement system

DPR/DGS plans to plant new trees & landscaping in the

plaza (a source of loose materials) Unanswered questions include who will vacuum &

maintain the permeable pavement system

This is a baseline question

DC does not have an established track record ofmaintaining the park (trimming trees & hedges, repairingthe trench drain)

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THE BOTTOM LINE

A permeable pavement system is a complex,engineered system, with numerous points of possiblefailure, and requires regular, systematic maintenance

The plaza area has many features which are highly

problematic for a permeable pavement system (mulch,organic materials, a building, trees, shrubs, grass)

Permeable pavement is best suited to lessenvironmentally complex areas (like parking lots with

limited vegetation) Given the small surface area involved & the high cost, it

is an ineffective way to manage stormwater

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SUGGESTED APPROACH

Defer finalizing plans for plaza improvementsuntil plansfor playground improvements are finalized

Restore & augment the trench drain system & remediateerosion

In developing plans for plaza improvements, preserve the

1947 NPS plaza design by steps like replacing theHawthorn trees with similar trees, restoring the plazasprivets, & planting compatible bushes or plants in the 2oblong planters

If it is conclusively determined that the permeable

pavement system is technically & environmentally superiorto the trench drain system & that maintenance questionscan be resolved, consider deployment of permeablepavement in areas of the park where it will not requiremodification of the existing plaza design

Documents

Reeder & Pols presentation to ANC 1C-Dec 3 2014