Creek Watershed Management Plan
Client: Unified Sewerage Agency
The flood work PWR
staff completed for Fanno, Summer, and Ash Creeks was motivated
by our previous work developing a comprehensive watershed management
plan covering not only flood management but water quality, watershed
health and many other characteristics. The plan was developed
by PWR staff while at KAI in cooperation with a multi-disciplinary
team and a project committee that included public stakeholders.
Our model calibration in this basin used two flow gauges -
one far upstream in the watershed, and one near the mouth, and
led to important advances in how watersheds should be modeled.
These advances were later incorporated into the calibration update
of Portland's Johnson Creek. The Fanno Creek management planning
project made extensive use of powerful spreadsheet-based model
development and QA/QC tools that are unique to Pacific Water
In addition, we
examined water quality records, simulated pollutant loadings
and concentrations with SIMPTM and developed important relationships
for TSS and sediment transport and between air and stream temperature.
Finally, we used GIS extensively not only to create informative
maps but even more
to develop model input parameters themselves and to process model
outputs into readily understandable form.
The management action plan that resulted identified specific
water quality and flood management projects along with community
based enhancement projects and non-structural project and programs
that should be implemented to improve water quality, reduce flooding
and restore riparian habitat. Many of the highest priority stream
restoration projects identified by the plan have already been
designed and constructed.
of West Linn Stormwater Master Plan
Client: City of West Linn, West Linn, Oregon
The city of West Linn required a comprehensive
update to their existing 1996 Storm Drainage Master Plan. The
new Master Plan will account for recent development within the
city limits, particularly in the Tanner Creek watershed. This
update will emphasize an assessment of the exiting stormwater
collection and conveyance systems as well as watershed management
for improving water quality. Services included development of
GIS coverages of the drainages within West Linn.
The results were used to create a HEC-HMS
hydrologic model of the watershed. The HEC-HMS model is used
to estimate flow rates and volumes within the system. Computed
flows will be used to analyze the capacity of the existing system
as well as improvements required. Water quality was modeled using
SIMPTM, PWR's unique pollutant wash-off model. Based on water
quality modeling results, new and existing maintenance practices
were optimized and future water quality facilities identified.
All findings and recommendations will be presented in the new
The project has been broken into two
phases. The first phase, which has been completed, involved the
development of the engineering and natural resources related
information and analysis. The second phase involves a public
process needed to formulate, evaluate and prioritize the various
aspects of the comprehensive management plan. The second phase
is currently underway.
Creek Master Plan Update
City of Portland BES
Principals now with PWR updated the hydrologic and hydraulic
models from the comprehensive 1995 Johnson Creek Resource Management
Plan (RMP) effort to reflect more recent calibration data and
new methods for modeling local runoff, stream channel storage,
and split flows through the Lents area. The resulting models
provided much improved predictions throughout the watershed and
especially through and downstream of the Lents area. Also, they
are very similar to the XP-SWMM model that the City later developed,
so much of the inputs from this modeling update were used directly.
Most of this work was done by Mr. Jelen with support from Mr.
Sutherland and Dr. Matin, and made much greater use of spreadsheet
automation of modeling and QA/QC processes.
Client: Clean Water
Services (formerly Unified Sewerage Agency), Hillsboro, Oregon
PWR served as the lead firm coordinating water resources GIS
and hydrology and hydraulic modeling with two supporting engineering
teams and three environmental science teams including our partner
Fishman Environmental Services. This $2 million project encompassed
over 460 square miles of watersheds and 570 miles of streams
and rivers, and spanned much of Washington County in what was
probably the largest watershed project of its kind in this state.
PWR completed the watershed management planning for about
120 square miles of this - nearly all of the watersheds draining
the Portland West Hills to the Tualatin River, including Fanno
Creek, Rock Creek (including Beaverton Creek and its tributaries)
and several smaller streams, that together drain most of the
urban areas of Washington County.
HEC-HMS flow models were created for 72-hour winter design
storms and can also be used for 24-hour designs or for continuous
flow simulations to support wetland hydrology or water quality
design. HEC-RAS flood elevation/profile models were completed
for over 70 miles of rivers and streams. These tools were used
by PWR to evaluate not only hydraulic deficiencies but also fish
passage issues for up to 600 identified culverts supporting ESA
25/26 Level 1 Watershed Assessment
Client: Lower Columbia Fish Recovery Board
PWR, as a subconsultant to Economic and Engineering
Services, Inc. (EES), has developed an efficient Level I assessment
for the Cowlitz and Grays-Elokoman watersheds. This Level I work
used existing data and reports to the maximum extent possible.
The primary goals were to review existing data and to determine
the adequacy of the information for water quality and quantity
modeling in two Water Resource Inventory Areas (WRIAs). The focus
of this effort was to bring together the data collected with
regard to water quantity and create an accounting between known
water inputs, losses, and flow among the various hydrologic pathways.
A summary of estimated flows / volumes
for each of the major hydrologic pathways in both WRIAs has been
presented. An assessment of discrepancies identified within the
existing databases was performed. A summary of water quality
impairment was also presented with an assessment of past trends
and present regulatory compliance.
Additional work phases that are currently
underway will involve the development and calibration of detailed
HSPF hydrologic models for several subbasins throughout the study