To: City Council/Planning Commission
From: Jon Holan, Community Development Director
Vergie Ries, City Manager
Date: April 3, 2000
Subject:
For this work session staff has prepared this memo summarizing Metro's Title 3: Water Quality and Floodplain Management as well as the program Forest Grove developed in conjunction with the Unified Sewerage Agency, Washington County and the other cities of Washington County to substantially comply with the Title 3 regulations. The differences between the two programs are explained along with how the program applies to the community
Water quality is a crucial component to the region's continued livability and long term economic health. Title 3, an integral part of the Metro Urban Growth Management Functional Plan, is intended to address water quality and floodplain management in the region through the development of performance standards for the protection of streams, rivers, wetlands and floodplains. In addition to adopting performance standards, Metro also adopted a Model Ordinance that Cities and Counties can use to be in compliance with the Title 3 standards.
The Title 3 performance standards adopted by Metro are separated into two categories, water quality and floodplain
management.
The key water quality provision requires a vegetated corridor along streams and around wetlands. The corridor width
is based on the area drained by the stream and the topography of the area. Exhibit A summarizes Metro's standards.
For primary water features (which includes perennial streams draining more than 100 acres, wetlands, natural lakes
and ponds), the corridor ranges from 50 to 200 feet depending on the slope. For secondary water features (which
include intermittent streams) draining more than 50 acres the corridor ranges from 15 to 50 feet. It maybe noticed
from Exhibit A, that Metro's standards do not apply to perennial streams draining less that 100 acres or intermittent
streams draining less than 50 acres. Further, there is no requirement to enhance degraded vegetated corridors.
Further, Metro's provisions allow for the development of lots that would be rendered unbuildable by the strict
application of the standards. Other provisions include a requirement to allow density transfers for the vegetated
corridor area and a requirement to control erosion.
The key flood control provisions require balanced cut and fill within the floodplain, prohibit the storage of unregulated
hazardous materials, and require the Federal Emergency Management Agency (FEMA) maps be supplemented with 1996
flood inundation area and other pertinent data if available.
The City of Forest Grove worked in conjunction with the Unified Sewerage Agency (USA), Washington County, and
the other cities of Washington County to develop a consistent county wide set of regulations to substantially comply
with Metro's Title 3 regulations. A number of outside agencies and groups including the Tualatin River Keepers,
the Audubon Society of Portland, the Homebuilders Assodiation, and the Westside Economic Alliance reviewed this
compliance report. These efforts led to a set of development standards adopted by USA and found by Metro staff
to substantially comply with Title 3. The difference between the two programs is described below. This was the
approach USA and the local jurisdictions used 9 years ago to develop a coordinated stormwater management system.
This earlier program, called Surface Water Management (SWM) provides one set of rules for all jurisdictions within
Washington County to follow.
A Washington County unified approach to Title 3 made sense for two other reasons. First and foremost is that USA
holds the National Pollutant Discharge Elimination System (NPDES) permit for all the jurisdictions in its service
area. This means that USA is the responsible entity for the quality of the stormwater that drains into the Tualatin
River. Secondly, USA was in the process of updating their Design and Construction Standards for Sanitary Sewer
and Surface Water Management, (SWM standards) which Forest Grove implements. This allowed for the Title 3 regulations
to be folded in to the Design and Construction standards.
Through the SWM program, jurisdictions in Washington County already met two of the performance standards contained
in Title 3, erosion control and balanced cut and fill in floodplains. Erosion control standards require the use
of silt fence, gravel construction entrances, and dust control mechanisms. Balanced cut and fill allows for appropriate
development to occur (as regulated by the land use zone) in the floodplain while reducing the risk of flooding,
preventing or reducing the risk to human life and property, and maintaining the functions and values of floodplains.
The flood management standards are in addition to local, state, and federal restrictions governing floodplains
and flood hazard areas. This is consistent with federal requirements to allow for appropriate intrusions into the
fioodplain and minimize potential legal issues.
The key water quality provision requires a vegetated corridor along streams and around wetlands. The corridor width
is based on the area drained by the stream and the topography of the area. For year round streams, the width varies
from 50-200 feet depending on slope and type of water feature. For primary water features (which includes perennial
streams draining more than 100 acres, wetlands, natural lakes and ponds), the corridor ranges from 50 to 200 feet
depending on slope. For secondary water features (which include intermittent streams) the corridor ranges from
15 to 50 feet. Intermittent streams draining 10 to 50 acres require a vegetated corridor of 15 feet, while an intermittent
stream draining 50-100 acres require a 50-foot vegetated corridor. Wetlands less than 0.5 acres require a vegetated
corridor of 25 feet. Exhibit B Provides a graphic representation of the USA required vegetated corridors.
Metro has accepted the USA standards as substantially complying with Title 3 requirements.
Similar to Metro, the new USA standards also require a vegetated corridor up to 200 feet depending on the nature
of the water resource and the steepness of the adjacent land. Exhibit C provides a matrix which compares the performance
standards contained in Metro's Model Ordinance to the to the requirements adopted by USA. One of the main differences
is that USA requires that degraded vegetated corridors must be enhanced to a good condition, whereas Metro only
encourages that enhancement take place. USA developed a set of standards that are used to determine the condition
of a corridor.
A second difference, as illustrated in Exhibit D, is the ability under the USA regulations to adjust the width
of the vegetated corridor in response to specific site conditions. One option is to average the width of the corridor
if the corridor is certified to be in a marginal or degraded condition. Averaging is not allowed in areas certified
to be in good condition. Maximum encroachment allowed for a project site is 20% of the frontage length of the vegetated
corridor by 20% of the required width. The area of encroachment must be replaced at a 1:1 ratio.
A second option is to reduce the overall width of the vegetative corridor. Vegetated corridor reduction is allowed
if the corridor is certified to be in a marginal or degraded condition, extends 125 feet or more from the edge
of the stream or wetland, and the vegetated corridor averaging option is not practicable. The maximum reduction
allowed for a project site is 20% of the required vegetated corridor. Vegetated corridor reduction cannot be used
in conjunction with vegetated corridor averaging.
USA, under the authority of the federal Clean Water Act, began enforcing the new performance standards as of
February 4, 2000. The City, through its intergovernmental agreement (IGA) with USA, implements these standards
for all new development within the city limits. In order to comply with Metro's Title 3, the City is required to
amend its Zoning and Land Division Ordinances to reflect these standards.
For Forest Grove the majority of the required vegetated corridors will be set at 50 feet due to the generally flat
nature of the land. There are a few isolated areas in the northwest section of the City where larger vegetated
corridors may be required. The regulations also allow a property owner whose land is entirely within the 50-foot
corridor to develop their land. The regulations do not apply to streams that are already piped, including several
tributaries of Council Creek in the Forest Grove area. The expanded flood management area includes not only the
Federal Emergency Management Agency's 100-year floodplain but also land identified in updated flood studies for
the floodplain area surrounding Gales Creek mapped during the 1996 floods. Overall, the adoption of the USA requirements
allows for Forest Grove's water quality and floodplain regulations to be consistent with other jurisdictions in
Washington County.
City Staff, through possible revisions of its IGA with USA, is exploring the feasibility of USA reviewing and approving
all stormwater and sanitary sewer components of development projects. This would allow the development community
to submit all improvements to the surface water and sanitary system to one review body, instead of USA reviewing
just the stormwater portion of the system.
|
Protected Water Feature Type |
Slope Adjacent to Protected Water Feature Type |
Width of Vegetated Corridor |
| Primary Protected Water Features | <25% | 50 feet |
| Primary Protected Water Features | >25% for 150 feet or more | 200 feet |
| Primary Protected Water Features | >25% for less than l50 feet | Distance from starting point of measurement to top of ravine, plus 50 feet. |
| Secondary Protected Water Features | <25% | 15 feet |
| Secondary Protected Water Features | >25% | 50 feet |
Sensitive Area Definition / Protected Water Feature Type |
Slope Adjacent to WQSA / Protected Water Feature |
Width of Vegetated Corridor |
Requirement for enhancement of vegetated corridor. |
|||
|
USA Standards (1) |
Metro Code (2) |
Same for both |
USA Standards (3) |
Metro Code |
USA Standards |
Metro Code |
| • Streams with intermittent flow draining 10 to <50 acres. | Not Protected | <25% | 15 feet | 0 feet | First 15 feet must be in "good" condition. | Encouraged, not required |
| • Streams and springs with intermittent flow draining >50 to <100 acres. • Wetlands <0.5 acres |
Secondary Protected Water Features (4) | <25% | 25 feet | 15 feet | First 25 feet must be in "good" condition. | Encouraged, not required |
| 25 feet | 0 feet unless mapped | |||||
| • Existing or created wetlands >0.5 acres; • Natural lakes and ponds; • Rivers, streams and springs with year round flow; and • Streams with intermittent flow draining >100 acres. |
Primary Protected Water Features (5) | <25% | 50 feet 50 feet |
50 feet 0 feet |
First 50 feet must be in "good" condition or whole buffer if less than 50 feet | Encouraged, not required |
| Streams with intermittent flow draining • 10 to <50 acres • >50 to <100 acres. |
||||||
| Not Protected | <25% | 30 feet | 0 feet | |||
| Secondary water features (4) | 50 feet | 50 feet | ||||
| • Existing or created wetlands; • Natural lakes and ponds; • rivers, streams and springs with year round flow; and • Streams with intermittent flow draining >100 acres. |
Primary Protected Water Features (5) | >25% | 50 - 200 feet. Measure in 25' increments from starting point to top of ravine, plus 35' from top of ravine (6). | 50 - 200 feet. If measure in 25' increments from starting point to top of bank, plus 50' from top of bank (7). | First 50 feet must be in "good" condition or whole buffer if less than 50 feet | Encouraged, not required |
