HomeMy WebLinkAbout1989-0620 COMP PLAN FINDINGSBEFORE THE CITY COUNCIL
CITY OF ASHLAND
JACKSON COUNTY, OREGON
JUNE 6, 1989
IN THE MATTER OF PLANNING ACTION #89-027, REQUEST FOR:
1)
APPLICANT:
)
)
AMENDMENTS TO THE ASHLAND COMPREHENSIVE PLAN TEXT )
RELATING TO POLICIES REGARDING DEVELOPMENT IN FLOOD )
PRONE AREAS; )
)
ORDINANCE REVISIONS TO CHAPTER 18.62 OF THE ASHLAND )
MUNICIPAL CODE PERTAINING TO DEVELOPMENT REGULATIONS)
WITHIN THE 100-YEAR FLOODPLAIN. )
)
THE ADOPTION OF FLOODPLAIN MAPS ALONG ASHLAND, BEAR )
AND CLAY CREEKS. THE PROPOSED FLOODPLAIN CORRIDOR IS)
IN ADDITION TO THE 100-YEAR FLOODPLAIN AREA )
ESTABLISHED BY THE FEDERAL EMERGENCY MANAGEMENT )
AGENCY (FEMA), AND IS A MODIFICATION OF THE EXISTING)
FLOOD HAZARD AREA ESTABLISHED BY THE CITY. )
)
CITY OF ASHLAND )
)
FINDINGS,
CONCLUSIONS
AND ORDERS
RECITALS:
1) The several hundred affected tax lots are located within
adjacent to the floodplain of Ashland, Bear and Clay Creeks.
2) The applicant is requesting:
and
a) AMENDMENTS TO THE ASHLAND COMPREHENSIVE PLAN TEXT RELATING TO
POLICIES REGARDING DEVELOPMENT IN FLOOD PRONE AREAS;
b) ORDINANCE REVISIONS TO CHAPTER 18.62 OF THE ASHLAND MUNICIPAL CODE
PERTAINING TO DEVELOPMENT REGULATIONS WITHIN THE 100-YEAR FLOODPLAIN.
c) THE ADOPTION OF FLOODPLAINMAPS ALONG ASHLAND, BEAR AND CLAY CREEKS.
THE PROPOSED FLOODPLAIN CORRIDOR IS IN ADDITION TO THE 100-YEAR
FLOODPLAIN AREA ESTABLISHED BY THE FEDERAL EMERGENCY MANAGEMENT AGENCY
(FEMA), AND IS A MODIFICATION OF THE EXISTING FLOOD HAZARD AREA
ESTABLISHED BY THE CITY.
3) Type III amendments are applicable whenever there exists:
i. A public need;
ii. The need to correct mistakes;
iii. The need to adjust to new conditions; or
iv. Where compelling circumstances relating to the general public.
4) The City Council following proper public notice, held Public
Hearings on April 18 and June 6, 1989, at which time testimony was
received and exhibits were presented.
The City Council approved the application as prepared, on June 6, 1989.
Now, therefore, The City Council of the City of Ashland finds and
concludes as follows:
SECTION 1. FINDINGS
1.1 The Planning Commission hereby incorporates by reference
the Floodplain Corridor Maps and Physical and Environmental
Contraints Map noted as "Exhibit A", the Staff Report noted as
"Exhibit B", written testimony in opposition to the proposal
designated with a "O", written testimony in support of the proposal
designated with a "P", and the minutes from the public hearings
on this proposal held on April 18 and June 6, 1989, noted as
"Exhibit C".
SECTION 2. CONCLUSORY FINDINGS
2.1 The City Council finds that it has received all information
necessary to make a decision based on the testimony and exhibits
received.
2.2 The City Council believes that the proposed request meets the
criteria for a Type III amendment found in Chapter 18,108,080.
Specifically, the Council believes that there exists compelling
circumstances relating to the general public welfare which warrants
such amendments and, therefore, the Council makes the following
findings:
The City of Ashland's current plans and ordinances do not prohibit
development in areas subject to flooding, but require that if
development is to occur, it be elevated above the 100 year flood.
Non-residential construction can develop at or below the 100 year
flood level, if certain flood-proofing measures are taken. This is
basically a repetition of the required FEMA measures.
However, the Council has found that a considerable body of evidence
exists that suggests that the FEMA study, that we rely on to
identify the areas of flood hazard, is not accurate, that the
limitations of the FEMAmethods bypassed areas of significant risk,
and that the current regulations that purport to reduce or
eliminate risk of flooding are inadequate.
The evidence that exists is contained in the following facts:
1) The FEMA maps were drawn to identify the elevations above mean
sea level of the 100 year flood. They relied on 1" = 400' and 1"=
1,000 ' maps of Ashland that were based on air photography.
Because of this, the elevations supplied often are inaccurate by
a factor of 2 or more. The City has one survey, which shows that
the 100 year flood is only 1.6 feet above the flowline of Ashland
Creek, when the FEMA flood is supposed to be 4 feet above the creek
at this point. Therefore, the FEMA data cannot be relied on to
accurately establish the flooding level. In addition, many of the
100 year floodplain levels on Clay Creek are at or below the
surface of the ground when they are located on the site.
2) The FEMAstudy relies on "best case" assumptions in modeling the
flood situation.
The FEMA study used a computer to model the flood levels. It
starts with flow assumptions. There were only 18 years of data
when the study was done, so FEMA extrapolated from this and other
data from this area, including the Applegate River, Butte Creek,
and others. The oldest data was a 55 year record of Bear Creek at
Medford. The only flood used to calibrate Ashland Creek model was
the 1974 flood, that was a 30 year flood. Therefore, the flow data
could vary considerably from the actual conditions in a flood.
FEMA also assumed that during a flood, the stream would remain
confined to its natural channel, that there would be no culvert
obstructions, and that when a culvert was too small to pass the 100
year flood, the excess water would flow over the top of the street,
and back in the channel. They also stated that "In the last few
years many culverts have been replaced or enlarged, and a general
channel cleanup has been undertaken to reduce debris and allow
streams to flow properly". While two culverts were enlarged in the
City proper, most are the same size as in 1974. In addition, it is
evident that there is much vegetation and debris in the channel
that would be available to clog culverts should a severe flood
occur.
The mechanism that allows streams to meander is that the stream
will cut a new channel when the old one is blocked. The 1974 flood
showed that mechanism at work, both in areas where there were no
culverts, and at the Hersey Street Culvert. Ashland Creek, during
a 100 year flood, flows at a rate of about 2300 cubic feet per
second (about 1,000,000 gallons per minute), and at speeds between
10 and 20 miles per hour. The velocity and volume allow the creek
to cut a new channel with surprising speed and force.
It appears that the main assumptions of the FEMA study do not
represent a realistic flood scenario. Based on our knowledge of
past incidents, it appears that in every case of severe flooding
in Ashland and Bear Creek, 1) there was a large amount of debris
in the flood waters, 2) culverts were blocked, 3) there was new
channels cut due both to natural debris dams and blocked culverts.
Therefore, the FEMA 100 year floodplain does not cover known areas
of flooding as recently as 1974. Photographic evidence of these
incidents are contained as part of the whole record.
Also, a large body of knowledge on the historic floods of Ashland,
Bear, and Clay Creeks has been compiled from newspaper articles
dating back to the 1800's, which supports the above assertions.
This record of historic floods has been instrumental in helping
City staff to identify those areas that are in a geologically
active floodplain, and have some degree of hazard.
3) The three creeks are violent in flood, and have a history of
establishing new channels in floods.
Photographic, anecdotal, and scientific evidence has been presented
which shows that flooding on Ashland Creek was violent, and could
involve hazards other than simple inundation. The force
characteristic of a creek that would cut a new channel, when
directed against residential homes, would quickly destroy them. It
would also destroy any public improvements in the area, such as
streets and sewer and water lines.
The existing regulations permit housing in areas that would be
subject to inundation, violent stream flows, and debris flows,
endangering property and lives.
4) In addition, many of the flood prone areas are considered poor
choices for development because of soil and high ground water. This
is particularly true of Bear Creek, whose floodplain contains clays
soils of high shrink-swell potential, and have a very shallow
ground water table, at times on the surface for months at a time.
SECTION 3. DECISION
3.1 Based on the record of the Public Hearing on this matter, the
City Council concludes that the proposal for:
a) AMENDMENTS TO THE ASHLAND COMPREHENSIVE PLAN TEXT RELATING TO
POLICIES REGARDING DEVELOPMENT IN FLOOD PRONE AREAS;
b) ORDINANCE REVISIONS TO CHAPTER 18.62 OF THE ASHLAND MUNICIPAL
CODE PERTAINING TO DEVELOPMENT REGULATIONS WITHIN THE 100-YEAR
FLOODPLAIN; and
c) THE ADOPTION OF FLOODPLAIN MAPS ALONG ASHLAND, BEAR AND CLAY
CREEKS. THE PROPOSED FLOODPLAIN CORRIDOR IS IN ADDITION TO THE 100-
YEAR FLOODPLAIN AREA ESTABLISHED BY THE FEDERAL EMERGENCY
MANAGEMENT AGENCY (FEMA), AND IS A MODIFICATION OF THE EXISTING
FLOOD HAZARD AREA ESTABLISHED BY THE CITY;
is supported by the evidence in the whole record.
Therefore, based on our overall conclusions, we approve Planning
Action #89-027.
Mayor
Date
Attest