HomeMy WebLinkAbout0561.091-
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December 12, 1991
HOHOP~BlE CITY COUNCIL
Palo Alto, Caltfornia
fEMA FLOOD INSURANCE PROGRAM --RESULTS OF
A fLOOD PLAIN STUDY TO DETERMINE THE NUMBER OF ~~ES
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lIKELY TO TRIGGER THE FEMA REQUIREMENTS IN fUTURE RfHODfLING
Members of the Council:
REPORT IN 8RIEf
The purpose uf this informational report is to present re5~lts of a staff
study to determine the number of houses t~.t will potentially be affected by
existing f8HA regulations in the event Gf future remodeling. In summa~y, the
study revealed that approximately 29 percent, or 1,236 of the 4,265 single
f,~ily res1dences located within the flood pl~in ha~e suff;clent development
potential to trigger the FEHA requirements (e.;., raising the structure to an
elevation above the flood height) should they propose to ."emod.l to full
potential of t~e property. This study was conducted at the direction of the
City Co~neil in tneir meeting of Haren 4, 1991~ No City Council action is
recommended as I re~ylt of the study.
BACKGROUND
I. Introduction
Ba.sed on .experience .. ith applicati.on processing o~e.r the ~a.st two y-aars
(subsequent to the R-I building permit logj.m in 1;8;), it became
apparent that the hardsh1p of the f1o~d pla1n regulations ~n R-l
homeowners may ha~e been previously o~erstited. Only two applications
o¥er the p~st t~o years have run into zoning problems dYe to flo~d pla,"
consider~tions. There have been no other building permits which h!~e
triggered the flood p1ain regu:ations in that same time period. A
primary cause for the lEss-than-expected FEHA-re1ated problems is
undoubtedly the ecor.om~. While R-l permits for o~er-octupied
remodeling projects remain high, money is less available and refinancing
for major home improvements is less feasible than it was at onf time.
Speculati~e development in the R-l has declined substant~ally, due to
the real estate slump and lack of funds. B~caU5e the econ~y will
undoubtedly turn around at some point, it is ~ppr~priate to investigate
the FEHA issue for R·l pro~erty owners more carefully during this
r~cession, ~nalyzing the other variables which trigger the FE~A
re-qu1rements.
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II . T~e Ass i gn~nt
The City Manager's assignment to the Planning Depirt~nt was to
determine the number or percentage oJf residenc~s that (auld 1; kelJ' be
iffected by the flood plain reguhtions under c'Jrrent formul as and
wtlether or not the zoning regulation:; are contributing to the hardsh1p.
III. The Hypotheses
It _as hypothesized that the following variables were primary factors in
determinir-g whether or not l bu;'di~g permit wcu1ti trigger FEMA.
A. foundation heights in relation to flead w~. I~ the l-~ 2· and
e~en 3-foot lones, ma~1 houses currently have foundation h~ights
above the flood plain. The freshwater flood zones are limited to 1
and 2 feet above grade. We theorized that tho 1-to 3-foot flood
zones may encompass the majority of the flood plain, with tn~
higher 4-to B-foot saltwater zones actually being confined to the
commercial industrial districts. Within t~e R·) neighborhoods,
the majority of properties may already be in compliance.
B. Size of Addition. Minor additions t~ existing residenc~s do ~ot
trigger the FEMA regulations. Could it be that with the new, .are
stringent R-l re9ulations~ development potential has been reduced
~n the s1ngle family neighborhoods 50 t~at even if the homeowners
·~ax out· the re~afning potential on the lot, the F[~A
requirements are not trigger~d?
IV. The Investigation
The staff study involved the following steps:
A. Flood Contour MaR. A flood plain contour map _as produced, at 1-
foot e1evations, wnich describes spatially where the height ef
flood waters extend in the lOO-year flood, i.e., belts where flood
waters ~ould be 1 foot deep, 2 feet de~p? etc., ~p to 8 feet.
This information was superimposed on the zoning map in order to
iscertiii"in the flood eTevation at any given lot. These cor.tours
are extrapolated from point survey info~aticn. ind theref~re are
not precise. But the exercise was ~aluable in making the types of
estimates needed here. The map is attached to this infarmationel
report.
B. Selgct Residential BlOCKS. Using the contour map, staff selected
20 representative b10cks with~n the var;ous R-l neighborhoods,
attempting to choose blccks ~ithin I single flood ele~at;on and
from the various subdiVisions built within the potential flooding
area.
C.
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Oevelopment. Pottniial. File information was used to obtain the
approximate square footage of development existing for each lot
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'IIIiUtin the-salr.ple block., and t~at information was rellted to the
~AR poss1tJ.ie for the p:"'operty. The percentage of develD9ment
potential remaining for a11 propert1rs sampled ~a5 tne final
product derived. This figure Is included in the column labeled
~Bund{jut Pot~ntfll· in Table 1 and is the ratio of the allowable
FAR remaining on the lot tn the current hOIJse si ze.
D. Foyndation He;9~t. A su~vey of fou~dation heights within t~e
sample blocks wal cond~cted. The foundation heights were agii~
compared t~ the f100d elevation heights.
E+ Dev,lopment potential Triggerine fEMA. Using th~ value iccepted
b~ Public Yorks for e~isting square footage and the average value
ilccepted by the Building Division f.or new square footage, It .. as
statistically possible to calculate the number of residences in
the sample tkat would trigger the FEMA r~quirements, assyming tnat
tkey ipplied for a permit to R~ax Dut R the potential on the
property and the perlit involved no other interior improvem~nts.
These results are c~ntained in Table 1.
The Results
The follo\rJit"lg t .. ~ major conclusions 'Were drawn from the statist1<:al
analys; s. t
A. Based on current formuTas for uisUng and proposed values of
improvements, 29 percent cf the 4,265 resldences {l,236
residences) located ~ithin the flood plain have sufficient
development potential remaining to trigger the FEMA requir~nts
(e.g., that the structure be raised to an elevation above the
flood he;ght) should they propose to make an addition to the full
potential of the property. Tn~s conclusion is drawn from the
average remaining development potential of all blocks within the
sample sur~eyed.
B. The. !iigher f1 Dod plain elevatior.s extend much farther into the
single·family neigMborhoods than was expected. founaatio" heights
in the salt water f100ding areas are relatively level with g~ade.
[ncreased foundation heights of I to 3 feet can be accolTlTlOcfated
without zoning relief or di;ruption to neighborhood character.
However, should the residences within the 4-to B·foot zones be
required to comp1y with the FEMA requirements, they probab1y will
nep.d relief from the zoning ordinance and will create aesthetic
and neighborhood compatibility conflicts.
, The percentage:; do not account for addi tional remodel s which waul d: trigger
the requirement by doing combined interior lI1odifications which add to th~ ... alue
of the remOdel, or brand new residences which automatically trigger fEMA.
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CONCLUSION
Because there ha¥e been so few applications processed that trigger the FE~~
l"''!I]Ulat;''lns, and beci'JSe onl,)' approximately 1,236 homes have potential to
trigger full cotlipliance under curret1t formulas? a. z::me change at this tir.'/e
does not appear warrir.t!d.
Howe¥er, in the annual assessment of the Zoo)ng Ordinance, should staff note
an ;ncre~se in the r.umber of permits triggering fEMA requirements, stiff would
recommend that a~ ov~rlay zene be ap~lied to the floo~ plain districts,
allowing reduced or el~m1nated variance ~ees for those properties that need
daylight plan~ or maximum height variance (Qr flood plain reasons. In this
way. the financial hardship of the variance process wou1d be removed from the
peo~le who feel most damaged by the FEI4.A. regulations. Shff wouid recCJTTmend
that tha variance process be used in these cases, maintaining s~me d1screti~n
in the manner in which those homeowners exceed the loning requi r'"ements in
order to meet the FEMA reQulat1ons. Staff wouTd not recommend a blanket
lifting of the daylight plane ind maximu~ height requirement in those
neighbortlood"s because it could produce some very poor1y designed additions or
new homes, causing severe impacts on adjacent ~roperties and neighborhood
c.haracter.
Respectfully submitted,
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NANty MADOOX LYTLE
Zoning Administrator
(&(~I 8
;JllAM ZANER
City Manager
Attachments: Table I
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KENNETH R. SCHREIBER
Director of Planning and
Community Environment
Exhibit A, Approxim.te flood Elev.tion H.p
cc: Planning CommiSSion
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rabl. I. Charactertstics of Surveyed Block faces
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Buildout
Potential
,-lock Face I!!.an bng~ ~
II Chaucer b@tw@~n University & Hamilton. 19% ·42 B5% 2or.
N2 Fife between Boyc~ & Addison * 79% ·20 229% 67%
#3 Dana between Newell & Alester • 33% ·35 106% 38%
#4 St. Francis between Channing &
Embarcadero * 37% 7 66% 38%
15 Edgewood between cul-de-sacs. 59% 37 174\ 41);
16 Greer between Amarillo & Moffet Circle 64Y. 11 106% 65%
17 Maddux between cul-de-sa.c & Lorna Verde 951: 1.3. l30r. 103~
#8 Lama Verde between Louis & Stockton 54% ·11 98%
#9 Ames between Rorke & Louis 60% 12 • 103%
#10 Dri ftwood betweEn Arbutus & Evergre~n 54"; 14 · 75%
'11 Greer between Thomas & Thomas 41% 5.9· liB);
III Moreno between Colonial & Greer 33% -30 -64%
#13 Stockton between Maddux & T-1nter~ect1on 57% ·46 ·IWI.
114 Carmel Drive eQ% ·43 • 144);
~15 Ross between Ames & Barron Creek 93); 4.6· 259%
116 Otterson Court 4311: 25 -103);
117 Kenneth between Greer & Bend SO% 5.7-17411:
118 Indian between Oregon & Moreno 56r. 14 112~
U9 louis between Colorado & Clara 42); ·11 87l!:
120 Louis between Carina & Ross 31% -36 70%
Gross H~an • 53.9~
Gross Standard Deviation -32.3%
% of hom.< falling under 71% bul1dout potential· 71%
• Block-r~ces 1-5 are not 1n the sa1t water flood zone
and do not occur on Exhibit "A", Flood d~pths for
those block faces are 1nclud~d in the above table.
p: \NL \IIFAclta
61%
67%
54%
46%
30%
73%
89%
76~
33%
34%
55%
50%
48%
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Hean
0.5
1
0.7
0.2
0.9
0
0.5
0.3
0.1
0.4
0.5
0
0.7
1
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1.9
0.2
0.5
O.B
1.1
Foundation
Height
RInge nQd.
0 1.5
0 1
0 1
0 I 0
0 10 0
0 0 0
0 2 0.5
0 I 0.5
0 0.5 0
0 1 0.5
0 I 0.5
0 0 0
0 1 0.5
Q Z I
0 6 0.5
I 1 1
0 I 0
0 1 0.5
0 4 0.5
I 1 I
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Floor
Dept~
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1
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100 Yea, Flooa Water Depth
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OH .5-6 .2-3 .6-7 .3-4 .7-8
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EXHIBIT ft Aft
Approximate Flood Water Depth Map
On th. S.lt Water Flood Zon.'
SCALE: l' -1,00 O· Dec. 12. 1991
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NOTE:
Thls ma;p was wepal"ed by the C1ty of 1'.10 AHo Plann.inq Md P~bJh: VO'f'k ..
Oepj}f'tmnts:. It t!i. not i precis'! tapogript't1( ref~r~(\<:e afu.l 15. Mt t'-1 ~ lI$'id for
flood tOri£: det(,:'r"lb1I'1iltiQ(\, It wu pre!).lred for a spe(7fal 5tu<iy to s1'\o;JW
avprm(im~te location of flood e-leYit1ohS. Contours Were 1f1".erpolat~ f(Qm s)lot
elevations takE-n from data in tl1ft 1988 Army Corp, of fn9ine~ .. s ll!i.J!:ifttJ~~Q...W
ShoreJine Stydv A'10 refe:'fe-nc;ing the uses J~l/r Palo Alto (}u.a4r.ngl~.
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