12/9/2004; Wattles Boys and Girls Club 1

Wattles Boys and Girls Club 

9330 SE Harold Street, Portland 

Project Summary 

Project in Brief 

Project Type: Commercial stormwater retrofit (as part of an expansion and renovation project) 

Technologies: Landscape infiltration basin; infiltration planter; sand filter/infiltration gallery 

Major Benefits: • Runoff from more than 21,000 sq. ft. of roof was removed from the combined sewer. 

• The stormwater facilities remove more than 314,000 gallons of runoff from the sewer in a typical 

rain year, with corresponding reductions in runoff pollutants. 

• The project added 4,800 sq. ft. of native landscaping, improving the urban environment and the 

aesthetic appeal of the property. 

Cost: $56,581 (unit cost of $2.60 per sq. ft. of impervious area managed). The cost includes some 

landscaping that was not essential to the goal of removing stormwater from the sewer system. 

Environmental Services provided a $30,000 grant for the project. 

Constructed: Fall 2001 

Project Background 

The directors of the Boys and Girls Club were 

finishing plans for an expansion and renovation 

project in 2001 when they received information 

about the Willamette Stormwater Control Program1. 

The directors viewed a stormwater project as an 

opportunity to improve the appearance and 

surroundings of the heavily-used building, to help 

reduce combined sewer overflows (CSOs) to the 

Willamette River, and to provide valuable 

educational opportunities for the community. The 

Club owners also wanted to save money on 

stormwater utility bills. 

The plans for the renovation project originally 

specified a soakage trench to manage roof runoff 

from a 3,000 sq. ft. addition to the clubhouse. The 

designs were subsequently revised to manage roof 

runoff from the entire building. The Club submitted 

a grant application in May 2001 and Environmental 

Services accepted the project into the program. 

 

1 Environmental Service implemented the Willamette Stormwater Control Program in 2001. The Program offered financial grants and technical 

support for a series of projects to retrofit existing commercial properties with stormwater controls incorporating green technologies. The Program 

recruited these demonstration projects in order to research the feasibility, cost and performance of commercial stormwater retrofits in the area served 

by the combined sewer. The Program provided grant funds for eleven projects. The projects were completed by July 1, 2003.

Aerial view of the Boys & Girls Club in 2002 after 

completion of the project. North is at the top of the 

image; the patio planters are visible on the west side of 

the building and the landscape infiltration basins are 

visible on the south side (circled in red)
12/9/2004; Wattles Boys and Girls Club 2

Project Scope 

• Redirected runoff from over 21,000 sq. ft. of roof to a series of 

stormwater infiltration facilities. 

• Constructed three landscape infiltration basins and a subsurface 

sand filter/infiltration gallery. 

• Constructed two stormwater infiltration planters and a concrete 

drainage flume. 

• Disconnected several downspouts and installed subsurface 

downspout extensions. 

• Installed two small drywells. 

Notable features 

• Educational value: the stormwater planters, roof scupper, and 

concrete flume visually enhance the building entrance and provide 

educational opportunities for children visiting the club. 

• Stormwater capacity: the addition of small drywells increased the 

capacity of two stormwater facilities - a planter and an infiltration 

basin. 

 

Project Design 

Robertson, Merryman, and Barnes, a local architecture firm, designed the 

stormwater project as part of the expansion and renovation project. The 

project triggered the requirements of Portland’s Stormwater Management 

Manual because the expansion added more than 500 sq. ft. of impervious 

surface. 

The stormwater management goal was to provide complete on-site 

disposal of roof runoff from the clubhouse and gym, maximizing the use 

of surface landscape facilities within the space constraints of the site. 

Overview of the Stormwater System

• A total of 3,500 sq. ft. of roof drains to two infiltration planters near 

the entrance; one overflows to a small drywell within the planter and 

the second overflows through a sculpted concrete trench (“flume”) to 

linked landscaped infiltration basins. 

• There are three landscape infiltration basins along the south side of the 

building. 

o The western infiltration basin receives runoff from the planter 

near the entrance and from adjacent roof areas. It overflows 

into the middle basin. The two linked basins receive runoff 

from a total of 10,300 sq. ft. of roof. 

Small patio planter; 2004

Large patio planter;

note overflow for drywell

 (“pipe well”); spring 2003

Entrance at NW corner; note tip of 

large patio planter next to flag pole; 

spring 2003
12/9/2004; Wattles Boys and Girls Club 3

o The eastern infiltration basin receives runoff from 2,100 sq. 

ft. of roof; overflow is directed to a small drywell. 

• Runoff from about 7,700 sq. ft. of roof on the north side of the 

building is piped under the building to a combination sand 

filter/infiltration gallery, which also acts as an emergency overflow 

for the linked infiltration basins. 

Stormwater Capacity and System Components 

I. Introduction

The overall design goal was to meet Bureau of Development Services 

(BDS)2 standards for stormwater disposal. When BDS approved the 

project in 2002, the disposal standard for landscape facilities was to 

infiltrate at least 3 inches of runoff in 24 hours (approximately the size of 

the 10 year design storm). The design standard for the subsurface 

systems – the landscape systems that overflow to drywells and the sand 

filter/infiltration gallery - was to manage 3.8 inches in 24 hours (the size 

of the 25 year design storm). All design standards were current in 2002. 

 

The Natural Resource Conservation Service (NRSC) Soil Survey for 

Multnomah County classifies the soils as type 52A - urban 

land/Multnomah complex. The survey assigns an expected infiltration 

rate of 0.6 to 2.0 in. per hour. 

Geodesign, Inc. drilled seven borings near the site in 2000 for the 

proposed Lents Town Center Urban Renewal Project3

. The borings 

varied in depth from 20 and 26 ft. below grade; none of them 

encountered evidence of groundwater. Geodesign conducted infiltration 

tests in five of the seven boreholes at 5 to 10 ft. below grade. The tests 

confirmed that the sub-surface soils drain well: just one of these fallinghead tests had infiltration rates less than 30 in. per hour. 

 

2

 BDS is responsible for developing standards for stormwater disposal and inspecting projects to confirm compliance with 

those standards. 

3 Reported in Olson Engineering technical stormwater design report; project 6789, August 18, 2000.

Large patio planter;

note overflow for drywell

 (“pipe well”); spring 2003

Construction - small infiltration planter

with flume (note trench drain bringing 

roof runoff into planter); 2001

Excavated landscpe infiltration 

basin (note erosion and 

accumulation of sediment); 2001
12/9/2004; Wattles Boys and Girls Club 4

II. Facility Components

(See site plan for details, page 7) 

Infiltration Planter (NW corner of the building). 

Catchment Area: 1595 sq. ft. of roof

Facility Footprint4: 100 sq. ft.

Internal Volume: 35 cu. ft. 

Overflow: The planter overflows to a small drywell (“pipe well”). 

Capacity: The planter has a capacity that is approximately 40% of the 

internal volume of a standard eastside soakage trench 5 that would be 

necessary for a catchment of 1595 sq. ft. The soakage trench would 

have a footprint of 96 sq. ft. and an internal volume of 101 cu. ft.

Additional Information: 

• The planter is recessed into the sidewalk near the building entrance. 

It is 22 ft. by 4 ft. and about 6 in. deep. It has a ponding depth of 

approximately 4 in. 

• There is 18 in. of sandy loam lining the bottom. 

Linked System: Small Patio Planter, Two Landscape Infiltration Basins 

(South Side of Building)

Catchment Area: 10,306 sq. ft. of roof 

Facility Footprint4

 of the linked system: 1,760 sq. ft. 

Internal Volume: 500 cu. ft. 

Overflow: If the linked system reaches capacity it will overflow to the sand 

filter/ infiltration gallery. 

Capacity: The system has a volume that is almost double that of the standard 

eastside soakage5 trench that would be needed for a catchment of 10,306 

sq. ft. The soakage trench would have a footprint of 618 sq. ft. and an 

internal volume of 650 cu. ft. 

Additional Information:

• The basins have 4:1 side slopes and a ponding depth of 

approximately 6 in. They have an overall depth of 12 in. 

• Each basin receives roof runoff via subsurface piping. 

• Both basins have approximately 18 in. of sandy loam in the bottom. 

• The combination sand filter/infiltration gallery is approximately 15 ft 

long by 4 ft. wide by 5 ft. deep and buried 12 in. below the bottom of 

the middle infiltration basin. 

• The sand filter is 18 in. thick, sandwiched between two layers of 

drain rock (18 in. of rock above and 27 in. of rock below). 

 

4

 For the purpose of comparing the capacity of the facility with the standard eastside soakage trench, the footprint has been calculated as the 

wetted (ponded) surface area when the facility reaches maximum capacity. 5 The standard eastside soakage trench meets the City’s standard for complete stormwater disposal in soils that infiltrate at least 2 in. per 

hour. The City requires 24 ft. of trench per 1000 sq. ft. of impervious area (drainage catchment). The trench is 3 ft deep, 2.5 f.t wide, and 

filled with drainage rock. Flow enters the trench through a pervious pipe that travels the length of the top of the trench. Assuming a porosity 

of 35%, the trench provides an internal volume of approximately 63 cu. ft. per 1,000 sq. ft. of catchment.

Southwest infiltration basin just 

after planting; 2001

Southwest infiltration basin after a 

rain event; 2002

Southwest infiltration basin; 

October 2004
12/9/2004; Wattles Boys and Girls Club 5

• The planter is recessed into the patio area 

at the building entrance. It is 5 ft. by 5 ft. 

and approximately 6 in. deep. 

Landscape Infiltration Basin #3 (SE corner of 

the building).

Catchment Area: 2,120 sq. ft. of roof 

Facility Footprint: 300 sq. ft. 

Internal Volume: 75 cu. ft. 

Overflow: Any overflow drains to a small drywell 

(“pipe well”). 

Capacity: The basin has an internal volume larger than a standard 

eastside soakage trench sized for the same catchment (the 

soakage trench would have a footprint of 126 sq. ft. and an 

internal volume of 132 cu. ft.). 

Additional Information:

• The basin has 4:1 side slopes and a ponding depth of 

approximately 6 in. Its overall depth is 12 in. 

• It receives roof runoff via subsurface downspout extensions.

• Approximately 18 in. of sandy loam line the bottom of the 

basin.

Small Drywells (“Pipe Wells”) 

• The large planter and infiltration basin #3 (SE corner 

building) are both fitted with identical small drywells. 

• Each drywell is a 10-ft. section of 12 in. diameter pipe, sunk 

vertically. The pipe is corrugated ADS. The bottom 6 in. of 

the pipe is perforated and surrounded in drain rock. 

• The top (inflow point) of each drywell stands 4-5 in. above the floor of the facility; a standard flat 

grate covers the top of the pipes. 

• The drywells are not a standard design (but did not require a design appeal). 

Landscaping 

The vegetation in the landscape facilities, including the planters, is a combination of native and nonnative varieties. A range of trees and shrubs surround the facilities, providing visual interest and shade. 

They also serve to deter access to the basins. 

Irrigation system 

A permanent irrigation system was installed to serve the new landscaped areas. 

Schematic of pipe well 

Cross section of patio planter 
Site Plan of the Wattle’s Boys and Girls Club indicating stormwater facility locations and roof catchment areas. 

Stormwater Infiltration Planter Landscape Infiltration Basin 

N

Flume

1 2 

Sand filter/Infiltration gallery
7

Budget 

The final total budget submitted by the Club is $56,581. It does not include management and volunteer 

hours for planting the landscape. It includes costs for installing landscaping in areas that are not part of 

the stormwater facilities (see discussion following budget table). 

Environmental Services contributed $30,000 in grant funds to the project. The final budget is shown 

below in Table 1. 

Table 1. Wattles Boys and Girls Club Budget 

Task Item Item Cost Total Cost

Volunteer 

Effort

% of Total 

Budget

Project Management ?*

Design $15,327 27%

Architectural design $3,666

Engineering $9,536

Landscape design $2,125

Construction Management ?*

Site Preparation and Construction $22,893 40%

Landscaping $14,411 25%

Plant Materials $8,406

Plant Installation $1,000 ?*

Irrigation $5,005

Miscellaneous $3,950 7%

Permitting $850

Plumbing $3,100

TOTAL $56,581

* Costs for project and construction management were absorbed into the overall costs 

of the expansion and redevelopment project and are not available.

* Volunteer labor costs were not documented.
8

I. Budget Elements

Non-Construction Activities 

The total cost for non-construction activities, including design and permitting, was $16,177, comprising 

29% of the total budget. 

• Management

The final budget does not include an estimate for management costs; they were incorporated into 

the larger renovation project. 

• Design 

The total cost for design was $15,327. This cost reflects the substantial engineering effort, 

particularly for the sand filter/infiltration gallery, and the architectural design of patio elements 

such as the stormwater flume. The relatively high design costs may also reflect the last-minute 

change orders required to add the stormwater management elements to a project that was already 

in progress. 

• Permitting 

Permit costs were reported as $850. 

Construction Activities 

The cost of demolition, excavation, grading, construction, and landscaping was $40,404, comprising 71% 

of the total budget. 

• Site Preparation and Construction 

These were reported together in the budget as a total of $22,893. 

• Landscaping 

The cost of landscaping was $14,411. The plantings cost approximately $3.00 per sq. ft.; the 

irrigation system added about $1.70 per sq. ft. This is a relatively large proportion of the budget, 

although it does not account for installation by volunteer crews. The cost is not representative of 

the typical cost to landscape stormwater facilities – more than half of the areas included in the 

planting plan were outside the facilities. 

• Miscellaneous 

Plumbing was a relatively small part of the budget at $3,100. 

II. Cost Efficiencies 

Management 

The final budget does not include management costs for construction of the stormwater facilities. Those 

costs were absorbed into the management costs of the larger renovation project. There were likely 

substantial cost savings to implementing the project as part of the renovation project. 
9

Mobilization 

Staging and mobilization costs were probably minor since the stormwater project was part of a much 

larger expansion and renovation project. 

Conveyance 

An existing (unused) pipe in the foundation provided an easy option for conveying runoff from the north 

side of the building to the sand filter/infiltration gallery on the south side. 

III. Cost Comparisons

This project includes simple landscape facilities that could be applied in many commercial retrofit 

projects. The project also includes more complex features, such as the architectural elements in the new 

patio, that were feasible as part of the larger renovation project. 

The Boys and Girls Club summary budget is incomplete and requires adjustments in order to develop an 

estimated final budget. For cost comparison purposes, it is reasonable to increase the overall budget by 

10% to account for the management and landscape installation activities. It is also valid to halve the listed 

landscaping costs (approximately $15,000) since the stormwater facilities comprise less than half the total 

area that was landscaped. With these adjustments, the overall cost is approximately $55,000. 

Bidding and Permitting 

I. Bidding Process

The Boys and Girls Club contracted with Anderson Construction Company for all phases of the expansion 

and renovation project, including the stormwater project. Anderson sub-contracted the excavation work to 

Moore Excavation, Inc. 

II. Permits Required

Plumbing Permit 

A separate plumbing permit was issued for the downspout disconnections, additional stormdrain pipe 

connections, and overflow devices (including the sand filter/infiltration gallery and the small drywells). 

Commercial Building Permit 

The City required a commercial building permit for the expansion and renovation project; the permit 

covered all construction, including the stormwater management facilities.

Site Development Permit 

The City did not require a site development permit because the commercial building permit incorporated 

the range of reviews required for the entire renovation project (including the stormwater management 

facilities). 
10

Planning and Zoning Review 

Construction and implementation of the stormwater management facilities did not trigger requirements 

related to conditional uses, non-conforming uses, and overlay districts (trails, e-zones, plan districts, etc.).

Appeals 

No permitting appeals were required for the stormwater facilities or related components.

III. Permitting Issues

There were no permitting issues to report. 

Construction 

Anderson Construction Company was the primary contractor for the project. Anderson began construction 

began in April 2001 and finished the work in November 2001. 

Maintenance and Monitoring 

The Boys and Girls Club owns the facility and is responsible for maintenance. Environmental Services 

will monitor the performance of the facilities at the Club for at least five years, and perhaps longer. 

Confirming the hydraulic performance of the facilities will be a primary focus. Environmental Services 

will also regularly evaluate the level of effort required to maintain the facility, the success of the planting 

regime, and comments from the owner. 

Successes and Lessons Learned 

Adaptive design – the design successfully incorporates a variety of infiltration technologies to achieve 

different aesthetic goals and adapt to space constraints. The patio planters and the flume are very effective 

visual enhancements to the buildings entrance. 

Efficiencies – there were likely substantial efficiencies in the management of the stormwater project since 

it was integrated into a larger building expansion and renovation. Management costs were not reported in 

the budget summary. 

Landscaping – The completed landscaping did not conform with the landscape plan as originally 

permitted and approved. This situation is not atypical, particularly for landscaping efforts conducted by 

volunteers. Some plants were subsequently moved to locations that provide better growing conditions, 

and plants were added post-construction to replace those that did not survive.