HomeMy WebLinkAboutSDP202000011 Review Comments Critical Slope Waiver 2020-02-27 Christopher Perez
From: John Anderson
Sent: Thursday, February 27, 2020 1 1:06 AM
To: Craig Kotarski
Cc: Christopher Perez; Frank Pohl
Subject: Critical Slope Waiver Request [ SDP2020-00011] ; RE: WP0202000005 - Boys and Girls
Club, Northside, VSMP/WPO
Craig,
Engineering cannot support the critical slopes waiver request for this project in its current form,under current proposed design.
• While acknowledging relief from strict application of critical slopes preservation requirements should be granted to a
degree to help ensure safety of boys and girls attending the Club,no alternatives are presented.
(below,2/11,county staff wrote, `public safety is always the highest public purpose, in my view'—Engineering
supports a site design that is inherently safe for those who routinely visit or use the facility.)
• Please consider alternatives. Present several at least. Nominate preferred alternative to current design. Engineering
cannot support current design with recommendation of waiver approval,absent alternative consideration.
Note:Alternative analysis is a technical and not economic or cost-benefit analysis.
• Waiver request gives no indication cost influenced design to this point. In fact,letter from James R.Pierce,CEO,Boys
and Girls Clubs of Central Virginia,d.2/21/20,makes persuasive arguments that are not economic in the least.
• Yet it appears proposed design eliminates all retaining walls,not just very high walls(20'-30' single,standalone
retaining walls).
• Please consider range of design approaches available. A hybrid approach the relies on walls of modest height placed
farther from main activity areas/main building with less steep grading across critical slopes would position design
favorably relative to critical slopes requirements,and position Engineering to support an alternative design.
• Engineering,reviewing VSMP plan and waiver request,notes nearly all impacts to critical slopes are in fill sections,
that virtually all fill on critical slopes is 2:1 (image,below). 2:1 slopes would uniformly steepen existing critical
slopes. 2:1 fill slopes are problematic in multiple if not most settings.
• Once constructed,if erosion establishes patterns across 2:1 fill slopes,it is hard to reverse or stabilize 2:1 slopes. The
situation is made worse in this instance:fill placed on slopes rated susceptible to erosion,are then made steeper.
• Albemarle is engaged with minor to severe 2:1 (even 3:1)fill slope erosion at several commercial and residential
projects where slopes include significant vertical intervals.
• Most remedies have not worked to halt erosion on 2:1 fill slopes,not even after multiple attempts. Experience guides
response to proposed design/critical slopes waiver request.
• Fill slopes are more susceptible to erosion,since fill is less stable than cut underlain by consolidated,undisturbed
ground;this is why VESCH prohibits emergency spillways for SWM facilities in fill sections.
• Engineering is not positioned to recommend approval of critical slopes waiver than proposes no walls of any height in
any location(even modest 5-6' walls,or series of 3 or 4,5' high walls).
• Tiered walls of modest height could,in less than 20',eliminate elevation gain of 20'.
• If tiered walls are spaced,located not immediately adjacent to main activity centers/main building,and are protected
(access to tops of walls restricted)with landscape fencing,risk to girls and boys attending the facility,if not eliminated,
is minimized.
• There is no eliminating malicious intent of any human being. Walls are attractive to children. Children are
curious. Alternatives should consider wall placement,shielding walls,restricting points of access along walls,
especially tops,and at wall ends.
• Thought and care in design can significantly limit risk posed by tiered walls of modest height.
• Engineering recommends consider and present concepts that rely on slopes no steeper than 3:1,and tiered walls of
modest height. Engineering intends to recommend waiver approval of less-steep proposed fill slopes if a portion of
design objective is met through retaining walls of modest height.
• Engineering will not recommend strict application of critical slopes requirements to this project,or insist that a hybrid
3:1 slope-retaining wall design be limited to 0.45 Ac.critical slope impact.
1
• If revised impact exceeds cur...,.estimate of 0.45 Ac.,yet proposed(3:1)gra... ..as a better chance of long-term'
stability,if wall heights do not pose same risk as risk posed by 20'-30' walls,then Engineering will recommend the
preferred design alternative for critical slopes waiver approval.
Note:For the moment, Site and WPO plans received 1/31 and 1/22,respectively,take an all-or-nothing approach to
retaining walls. There is surely a middle-ground alternative design approach that address myriad facility use,safety,
resource protection,and technical county code objectives.
When considering alternatives,please:
• Apply 18-30.7.5 steep slopes standards,which are wholly appropriate for waiver request proposal that must reflect best
engineering practice to limit potential for erosion,and increase likelihood of post-developed slope stabilization. All
items at 18-30.7.5 are relevant(a./b./c./d.).
• Estimate total area of critical slopes that exist on TMP#06000-00-00-078A0;this value is reported in table format in
Engineering recommendation to Planning,along with proposed impact to critical slopes(0.45 Ac./current design).
(An estimate of total area of critical slopes that exist on this 216.69 Ac.parcel provides context(-0.45 Ac.impact)
relative to overall presence of critical slopes on the parcel under development.)
• Parcel acreage=216.69 Ac. A guess without real basis is 3-5%of this parcel is comprised of slopes steeper than 4:1
(critical).
• Could Timmons use county GIS topographic data layer to analyze extent of critical slopes on this parcel,as a
percentage?
Note:A close approximation is helpful,provides context,and is far better than a guess. Also,image caption,below.
Left:GIS critical resource map turned on;Right: GIS critical resource map with floodplain/stream buffer layers off.
Image right emphasizes presence of critical slopes. It's possible more than 5%of the total area of this county-owned parcel is
steeper than 4:1 (25%),or more than 10 Ac.of the parcel is in critical slopes. It would be helpful to know. It would be helpful
to report that proposed design impact of 0.45 Ac.is<5%of critical slopes that exist on-site,for example. Engineering would
also like to frame impact to critical slopes in context of site development LOD,6.49 Ac. 7%of area of disturbance is on
critical slopes. 93%of proposed development avoids critical slopes. Less steep alternative design with modest walls and
limited impact to critical slopes is a favorable design that Engineering can support.
2
E
0.%1 k \ 00-0•
.., —
&is, a
. k ,4,\ ...‘.., ...--...r,..wsill
..„
, 1.,..
' 1 .
,\,\ _.,,,,r \,tz4
'1 i ,.;--kr vt, ,; •.,,-.,_:e.' 4, _-- - ,, -...z.......
...-,0:-.• . , - -
t- , - foci 4,,,eli, 3,4 a 1...,..?.- ......._ • -.... -.....---- 1
)
...f.\,\\,
•• N.,,_ .
.44 -, =
,,
A ... ,
,-- -
1
4
,=,—,(17.,..,c , • . .9„,
_.........._,
.. , .0 . .._.: ,..
. i
i•-• _ -_ -,...II
c'Z's
1 \ /
•
.110,0•1 10.0/3 `,IN
reto 4.,a . kg
s..‘
qs•tuaqiv .
11114111k -7,-., . te,
---'
..,'S's 1/*C.--\ - - . •If.;":
114164.00-- yr',.. ,-s, , v .•'-":"-\ -
\11
; .
__,AIMI........
ui •-•.-
SIM •
sp.(
/:,
i. n v
se
i
ill
s
....
/IN,. .•
.i..:2\
--1-141."---..e."-111,14r,01i: li'11\1 .. ... .,.....'' .
•., ', • '..." _—
1, ' ''''Y'Y Pr NN04......N.,...\ if
11 Z
ri
.. ...
- i
)), 'cj,.._ .
(
. ./1//4 , .—* ':''.4 -: '
,_.........._._..Ls,_ ...,,,,- X ie, tel.' , ,,I „.•.- _
4..... ._
/ ----
...„ .....-:_-_,
—...............
.,(.(ii
---• A q .!Hp, (4„... .
/ % 't *II •4 ....------...-----__
. ... ,.. 7....
)0sti
ii .
..... A 0 : , •",. ,:.,A\... Iv
'-'--,u-,- • , .
...,4 ,..., \1/4 ii k '')",.t\\i.‘15:74-7 A WY l
, ,,,,,p,..,•...... \---7.,...' ( i -- .: -14'ifty tip vim il i i,
T \ s , ty • - ,i,,,,,,f( s...=
if
- ,
/ •' A ' '4 . i( VN. N .-----_---,,i,. ---z.,14 gi 741101%, 1
4: (Of.* a ...•.%.'. 7 11 1 ' 410° i jilitAwitif.ri
01)v / ' -:"INN." . ' •.."---'4,-,. 4 ' 41"
' Iiiki f
.5c)
i (
A . lotion i
\,410.1.--,Troar7:Or '„Nimik\i .A I r, ms iiii
/ A t
, 4
'S ,..N.41.,,,, 4 . . • 4:1 40.711A \ \..\
l' r,. "A„ ,..•-•zs-.7N- z.,,
.4.
r , - **.„. • 1 i 410
'1/4k,,, ' :emu ..k.,..z;.,
(1 g(r(rff \44,"4: L 4-7
, . C 441c ElLti , ird ! k%
ie,
4. I
ei
\ ‘• . V . ,
- ,,1 ',. ‘‘\ \ SCI,vA" ',f h Li../ l• 4
41 ,. dEr
•=14fa T. 7(' 4A-"e‘Jlifki 1p kt pAr,,:
411
\, ,VC.....11 (iv. ,__,W' ''.•14.._ ,4ft...et,,:lee '41e 14,-7441, A, 1
4., :4 _,A.-.40r,Ap444,4criiii.i, 1
\iiI F.
...,4:4,.... ... el
'Al---.11,1.-qopittv.- 14ftikifiii
'.'40e. r Z2,z-_--'•i,kt. k •,.._ ‘4\/A filiA"' '.:2‘r,7 44k kial.1) * k- 1
*1 111-4*.fkovil-e.,
1,,. ..7.-...,..,._. ......._Air.,,,,, .., , *, -„,..,_..„,,,„„• _ .,.,....... ,
1,„•7 Nii..—,-\ • 112..3„,41\ `.4‘ -----qt,i.\1:e.f,, 11111:11. y 4
_ 4. -, I it':
WP02020-00005,C4,ESC Plan,Phase III—proposed 2:1 slopes across critical slopes. Please note:Elev.490' to Elev. 530 is a
40-ft.unbroken vertical interval. Engineering requests design conform with standards at 18-30.7.5.c./d.
•
4
. - _: - _ - � Z% i
-- - - sim- - -520— - ' - 1 - re- -�lsf t - - ' i- - — 3� Y I - - j / .
— _ — 0 x*11r1* - '- // '
0
- - - ' - - _ _ - - - - -- _ _ / I - /// // //_
___,/, ,
-5/5, _--
_ _ _ _ - -
_ -
* DC
0.,
- - - - - _ s SF
, ,
-,
PS _ - _ - - - __ s ' �i su _, ,,I., ....,.‹.e -... ""'" / 7,,:0000111 ,--"
--- '... 1 l'it 1 A 1 1)' 'ti` -Qv'' --_- ---- --:.----------.' Il."'' 4 ;:,/
_ _ _ — _ 4'1111°',...f. 'cc,- ------- --:—..:---_—_—„."----- - -.... cp
III - - - - - - - - - - , -!-- ,-- SF �
!�� =%'i _
---- ---— --- -`l��'/ //�� /' '��-!li/I��'�� '�A'3''
_.__._
- == PS i B/M pS
4 ___ Alb. -'—'... ......------'"__------__ -,' ./j A\ .
- ....... INE 11101j.„---/....‹. .." -41 ----::7--------.- ----- -- -...". "-. — -- .- TP •ir.. , ,•
Thanks,Craig
best,J.Anderson 434.296-5832-x3069
John Anderson,PE,Civil Engineer II • (434)296-5832-X3o69
Community Development Dept. I Engineering Division
County of Albemarle 14oi McIntire Road
Charlottesville,Virginia 22902-4596
From:Craig Kotarski<Craig.Kotarski@timmons.com>
Sent:Tuesday, February 11, 2020 12:45 PM
To:John Anderson <janderson2@albemarle.org>
Cc: Bill Fritz<BFRITZ@albemarle.org>; Frank Pohl<fpohl@albemarle.org>; Christopher Perez<cperez@albemarle.org>;
U Lopez<Ilopez@milestonepartners.co>
Subject: RE:WP0202000005- Boys and Girls Club, Northside,VSMP/WPO
One question we have, as we prepare our special exception, is the reference to section 32.3.10(d), within 4.2.5.a.1
below. In looking for that,that section does not exist...is that actually pointing to a different section? Any help or info
would be great.
5
Thanks!
Craig
From:John Anderson <ianderson2@albemarle.org>
Sent:Tuesday, February 11, 2020 10:32 AM
To: Craig Kotarski <Craig.Kotarski@timmons.com>
Cc: Bill Fritz<BFRITZ@albemarle.org>; Frank Pohl<fpohl@albemarle.org>; Christopher Perez<cperez@albemarle.org>;
U Lopez<llopez@milestonepartners.co>
Subject: RE:WPO202000005- Boys and Girls Club, Northside,VSMP/WPO
Craig,
Thanks for your note. Since it may be difficult to establish or argue 18-4.2.5.a.3. -b./c.as rationale for granting a
modification, or waiver,your email may indicate likely best path(rationale) for granting a modification,or waiver; a./d.:
public safety is always the highest public purpose, in my view. Thanks again for your note.
best,J. Anderson
434.296-5832 -x3069
Sec. 4.2.5 - Modification or waiver.
Any requirement of section 4.2.1,4.2.2.4.2.3 or 4.2.4 may be modified or waived as provided herein:
a. Modification or waiver by the commission.The commission may modify or waive any requirement that is not sut:
1. Request.A developer or subdivider requesting a modification or waiver shall file a written request in accorc
pertains to a modification or waiver of the prohibition of disturbing slopes of 25 percent or greater(hereina
large-scale movement of soil and rock,excessive stormwater run-off,siltation of natural and man-made boc
and welfare factors")that might otherwise result from the disturbance of critical slopes.
2. Consideration of recommendation;determination by county engineer. In reviewing a request for a modificz
commission.If the request pertains to a modification or waiver of the prohibition of disturbing critical slope.
factors so that the disturbance of the critical slopes will not pose a threat to the public drinking water suppli
engineer shall evaluate the potential for soil erosion,sedimentation and water pollution that might result fri
of Virginia Erosion and Sediment Control Handbook and Virginia State Water Control Board best manageme
3. Findings.The commission may grant a modification or waiver if it finds that the modification or waiver woui
practices;and at least one of the following:
a. Strict application of the requirements of section 4.2 would not forward the purposes of this chapter or
b. Alternatives proposed by the developer or subdivider would satisfy the intent and purposes of section
c. Due to the property's unusual size,topography,shape, location or other unusual conditions,excluding
would result in significant degradation of the property or adjacent properties:or
d. Granting the modification or waiver would serve a public purpose of greater import than would be sen
From:Craig Kotarski<Craig.Kotarski@timmons.com>
Sent:Tuesday, February 11, 2020 8:42 AM
To:John Anderson<ianderson2@albemarle.org>
Cc: Bill Fritz<BFRITZ@albemarle.org>; Frank Pohl <fpohl@albemarle.org>; Christopher Perez<cperez@albemarle.org>;
U Lopez<Ilopez@milestonepartners.co>
Subject: RE: WPO202000005- Boys and Girls Club, Northside,VSMP/WPO
6
CAUTION:This message originated outside the County of Albemarle email system. DO NOT CLICK on links or open
attachments unless you are sure the content is safe.
John,thanks for your email. We are in the middle of preparing a Special Exception request for the impact to the critical
slopes.
We have looked at retaining walls, however those walls ended up begin over 30'tall. This poses a major safety issue for
the Boys&Girls Club, since they will have hundreds of students on campus during the day. Due to the nature of the
overall site and the ability to tie in the grades,they were ecstatic that the retaining walls could be removed.
Regarding the erosion control,the site does have its challenges. We have taken extra precaution to sit down with the
contractor, prior to finalizing this design to get their input. We worked hard to place erosion control measures in
locations that they can stay during construction, limiting additional earth movement. On this site,while certain slopes
are "critical", all of the slopes are steep and will require care and attention to detail during the construction process.
We are hoping to submit the Special Exception application next week. While there will be no action on it, prior to the
SRC meeting, hopefully it gives everyone a sense and some comfort of where we are going with this overall application.
Best,
Craig
From:John Anderson<ianderson2@albemarle.org>
Sent: Monday, February 10, 2020 6:12 PM
To:Craig Kotarski<Craig.Kotarski@timmons.com>
Cc: Bill Fritz<BFRITZ@albemarle.org>; Frank Pohl<fpohl@albemarle.org>; Christopher Perez<cperez@albemarle.org>
Subject:WP0202000005- Boys and Girls Club, Northside,VSMP/WPO
Craig,
Since proposed design requires Planning Commission modification or waiver of critical slopes requirements, which
depend on Findings(18-4.2.5.a.3.; Also, 18-4.2.5.a.1.,2. County Engineer waiver role),has Timmons considered retaining
walls rather than grading so steeply into critical slopes below contour elevation 515? We routinely see private
development propose tiered(or high)walls to avoid critical/steep slopes, and it is an option when designing to avoid
critical slopes. Glad to see that the proposed layout of building,paved areas, and site access nearly entirely avoids critical
slopes. The majority impact to critical slopes appears to be grading(with proposed grade quite steep),which may be
avoidable if design were to use retaining walls. I will review site and WPO plans,and hope to send comments by late
next week, if not a bit earlier—but critical slopes are a concern. C3.2, ESC plan,phase 1,proposes substantial grading to
install sediment traps on critical slopes(in preparation for upslope development). What design alternatives exist that
might lessen direct yet long-lasting impact of temporary ESC measures on critical slopes? Would retaining walls allow a
more measured ESC approach that causes less impact to critical slopes? Thanks for your time and patience—please feel
free to share any thoughts.
( I will review site and WPO plans as soon as possible.)
best,
J. Anderson 434.296-5832 -x3069
C4.0
SHEETS C4.1, C5.0 & C5.3
eak
n,.r,
�II 111
T : 1 111111N1 ,
L
c!5j::: : !!J
W.
J / /, / /
JJJI �
JJJJ JJI/ /Jr/ J I I
rt
II / I / I / /
/ p /•II
r
r J/r
/ /•
/ / M
/ JJJ i
I J J * n•-
I _ _
lI/ / r /
JJJ JJJ „�
cwmru stools Jr ,.....4-
JJJ J J J ��., `
on,
tr-
{ /. / t \ .:. .:{..r
-/ t / I
/ J -/ '". / /A
'fJ/ I,{J I1 /
/ J / tI /
., { { IJ 1 J!
J1 / {rJT / J J Ji 11
/ I
r
fIJ IJJ 1 I t J J /
tiJ / l/ / I J J / / J J J / I/ / / / / JJ J J I J / IIlJ1 // / JJ It 1 / /J I i JJ . J ! J , /
,
J � I / J J 1 :/ J J II 1I '
/ I / t J J / I / /
J JJJ JJJ J J J /1 J I J J J // J 11 J I, J / %I ; r , I i t'J I
I I I J J J J J I I I J J J J J J II r I /1 11 p r
I . J l i I.// i /I 11 J II I I !i s !/ ! /r $ .I f;I R 1 I 'r
. / ; / `IIJ, 11 II / IIJII II I .-.
! I �r I r 1 I ,I 1 11 I
r r 1 ' /
,y
e
C3.2
8
i 1 + ;
r l + 1 r ! 1 1 1 1 1 1 t 1 , • . 11 • 111 1 1 / 1 1 1 I r + ! r { lii ` 1'' 1i1i1 1 1 + 1 111 1 ; 110111
1 � � trt , lii1 + 1 / )If
' , 111iii11 ; v i r 1 i 1 ; ; 1 1 1 1 1 i i � 11i . aiil + ilr � 1 + 11ii � 1, ' 'l r , i l t r , i l t f ! ! 1 , , , , ! ! ! ! trfr , ll / Ir � 1 Ji , j , + / 1 , , fr 1 � / , / , , � , l � tll � , ri � liii ; :
ç
' li / r / J J I , I1 ! 1 /' / / rl ' / , ' l 111l '
/ 1 , ' /J / , I / ! / / r •J / 1 i , l I J I r , ! f f + / 1 ! 1 ! + ! ! t
/ J , , , , I / / J r ' / , , , , ! / / I 1 ' i f I ' l F r 1 1 l ! t ! 1 l i I��
I / I, // / /' r r / , , , r I, , , , / `, l ,� � J , rf rl j ,'� I rrli 1 1►
fi , // / , J/ �' �/ / I, ,' ,' / , , rr r r , / , , f r r /, r ; i♦, ! ! i l i1 /, , / / , '/ / !, / 'I /! , , ,/ ,/ , / , fJ/, , / , , 1,l / / • 1 If' r J' , r
/, '/ / /0 /
/ r/ / ' / rI I , I / ', / / ' / II , r l ti• ` , 'II , ;S fr ,/ ,, / ,/ // //,/,' ,/,' / ,/' /, ///IfI/ • • ,/+ r � /I,/,I/ / j/
/ // // , /, , ,' ,J /,/ /','}/ / ,' / ,' ,/// / I , /1 1'.-VI /'�,rIIIi j,� r r I ` '� , !./
r I / / / / / • / •./,/.I / / . 10 / 1 ( ‘ ./// w
/ ► / , r O. 0
Nal/ / //r,// / ' / //',`//,' / r///,/I•+.., / /' ,/ / r r r 1 ,I II II/ I J•
/ / , , , e/ I/ > ,} , �f , � , : / r, , •, , fit '
•
/ /r // / ,/ '' ///� > , , 1' i'r �/� // rrr r ,
, // , �I ,+ , J. �/ , , 1 1 1I l
�/ / , / , , __Aft y / �� __- fI // , rI , 1 tr I I ' ' rn
, i ,y , , , ,
NI 0
el 7,3
.1.,r/111 , Al. 7//4 il 0 t^ E
~� A f r /r� f/}/ } /} /I ; :s1:1•1'1/' 1,11,1,*.,f / ///I}fJ! /I' ,� \�•.,„�jr �.r��rN/f s / / I f/f } / } / f! } }f /f/} I/ i • �� r'� J'..• '. .�r'.. �. ^� '►.
vr / / /}/ / ! // �Q2 / ::/,
/ r/! }/• /y// !/ `� r' �``„ rrr ' rr I � .0
:::.•
�� e
• 0 / /*T4 l./ 8 L„--,-�} / JJ I ••• / r 1 r r++„.i150 r..' r e �r'^ " a'r,.r It
, vit
trE
IN;!1'
/ N ti_ •..„ .P r r f r r of r ru �M�e. r.'�' os 4. • r, .. i i
_/ g,/-, �„r.' /:' -.0 . t ' 1 1 f' 0,1i.i t I , ill t 1 1 1 11 1 ; I
/, / / r / / r / /} / '` f/} // a � tt „. ': i , t t 1 ':1
( t111.;
/ / /// / / r 1 1 �,1}} /}r , 0 /`/'/, / / ,t/'aC 'I/ 1•t( p %t...... :
f/ ! i 1 1 1 1 il./ 1111
/ /♦ , - / //* /' / // •
} / ' t t _ t .+,.I....- r 1-4.1 ; t tI,Y i1 t . \\ t/ , ,'} / /} f / } / f f! / /I ♦r.. • i rrrr"r• i 1tl , 111 1 ♦ 0 r tit 0 E
r /////}/ / /'J //i,, t Q•' ► _ 00 r.! . imilf _ ! t , ! 1+1 711ry, t. ♦, `y/k, % , • .° U
•