STORM WATER POLLUTION PREVENTION PLAN

FOR THE

FORMER RALSTON DISPOSAL SITE

Prepared For

ROCKWELL INTERNATIONAL CORPORATIONCEDAR RAPIDS, IOWA

Project No. 1166.0253

May 1995

Prepared by

Montgomery Watson11107 Aurora Avenue

Des Moines, Iowa 50322515-253-0830

I certify under penalty of law that this document and all attachments were prepared under mydirection or supervision in accordance with a system designed to ensure that qualified personnelproperly gather and evaluate the information submitted. Based on my inquiry of the person orpersons who manage the system, or those persons directly responsible for gathering theinformation, the information submitted is, to the best of my knowledge and belief, true, accurate,and complete. I am aware that there are significant penalties for submitting false information,including the possibility of fine and imprisonment for knowing violations.

for Rockwell International Corporation Date

for Rockwell International Corporation Date

for Rockwell International Corporation Date

TABLE OF CONTENTS

PAGESECTION 1 - INTRODUCTION ......................................................................................... 1

Background.................................................................................................................. 1Purpose......................................................................................................................... lContent......................................................................................................................... 1

SECTION 2 - DESCRIPTION OF POTENTIAL POLLUTANT SOURCES..................... 2

Site Location................................................................................................................ 2Site Activities/Site History........................................................................................... 2Land Use ...................................................................................................................... 2Site Security ................................................................................................................. 2Topography.................................................................................................................. 3Surface Water............................................................................................................... 3

SECTION 3 - STORM WATER MANAGEMENT CONTROLS ...................................... 4

Risk Assessment .......................................................................................................... 4Storm Water Management........................................................................................... 4Good Housekeeping..................................................................................................... 6Spill Prevention and Response..................................................................................... 6Sediment and Erosion Prevention ................................................................................ 6Employee Training....................................................................................................... 7Preventive Maintenance............................................................................................... 7Management of Runoff................................................................................................ 7Record Keeping............................................................................................................ 7Nonstorm Discharges................................................................................................... 7Visual Inspection.......................................................................................................... 7

SECTION 4 - STORM WATER SAMPLING ..................................................................... 8

SECTION 5 - ADMINISTRATIVE PROCEDURES .......................................................... 9

LIST OF FIGURES

FIGURE FOLLOWINGNO. PAGE

2-1 Site Location Map.................................................................................................. 22-2 Former Ralston Disposal Site Layout.................................................................... 22-3 Site Topographic Map............................................................................................ 33-1 Erosion Control...................................................................................................... 5

SECTION 1

INTRODUCTION

BACKGROUND

In 1972, the Federal Water Pollution Control Act, also referred to as the Clean Water Act,(CWA) was amended to provide that the discharge of pollutants to waters of the United Statesfrom any point source is effectively prohibited, unless the discharge is in compliance with aNational Pollutant Discharge Elimination System (NPDES) Permit. The 1987 amendments tothe CWA established a framework for regulating municipal and industrial storm water dischargesunder the NPDES program. On November 16, 1990, the Environmental Protection Agency(EPA) published final regulations that established requirements for storm water permits. Theserecent EPA regulatory changes require many industries and municipalities across the nation toapply for an NPDES Permit for all storm water discharges. In many cases, individual states havereceived NPDES Permitting authority from the EPA to write individual or general storm waterpermits. These NPDES Permits generally require dischargers to:

1. Eliminate nonstorm water discharges (including illicit connections) to storm watersystems.

2. Develop and implement a Storm Water Pollution Prevention Plan (SWPPP).

PURPOSE

A SWPPP is a document prepared to describe the various actions a facility will undertake toprevent the contamination of storm water runoff. The SWPPP has two major objectives: 1) tohelp identify the sources of pollution that affect the quality of industrial storm water discharges;and 2) to describe and ensure the implementation of practices to reduce pollutants in industrialstorm water discharges.

One of the most important factors in developing the SWPPP is the evaluation of alternativesavailable to a facility to control the contamination of storm water. These alternatives mightinclude administrative actions such as employee training or reporting and inspection procedures,nonstructural controls such as dust control and other good housekeeping practices, and structuralcontrols such as impermeable caps and storm water detention basins. In order to develop themost cost-effective plan, the various alternatives available must be considered for facilitiesindividually, tailoring the facility SWPPP to the needs and requirements of the individual site inconjunction with their storm water permit.

CONTENT

This SWPPP for the former Ralston disposal site (Ralston site) has been prepared to meet theobjectives and requirements of NPDES General Permit No. 1 (storm water permit) issued underthe authority of the Iowa Department of Natural Resources (IDNR). This report will addresssite-specific information including: site location, industrial activities, storm water managementcontrols, and storm water monitoring procedures.

SECTION 2

DESCRIPTION OF POTENTIAL POLLUTANT SOURCES

SITE LOCATION

The Ralston site is located in the NE 1/4, NW 1/4, Section 2, T83N, R7W, Linn County, Iowa.The Ralston site is situated north of 228 Blairs Ferry Road in northern Cedar Rapids, Iowa. Thelocation of the Ralston site is shown in Figure 2-1.

SITE ACTIVITIES/SITE HISTORY

The Ralston site consists of a former disposal area, a segment of Dry Run Creek, and a portion ofthe creek flood plain totaling approximately 1.5 acres. The steep banks of Dry Run Creek definemost of the northern edge of the disposal area. The site is accessed via a gravel road north fromBlairs Ferry Road between the Bauer residence to the east and Don's Automotive Service to thewest. A site layout map of the Ralston site is presented as Figure 2-2.

Little information is known conclusively regarding specific time periods, amounts, types andmethods of waste disposal at the Ralston site. From about 1956 to the mid-1960s the Ralston sitewas used by Rockwell International Corporation (Rockwell) as a disposal area for industrialwaste. An unknown amount of solid and liquid wastes including solvents, paint sludge, generalindustrial refuse, scrap metal, office furniture, and construction and demolition materials weredisposed at the site. The wastes were typically burned and spread in layers, as necessary, toaccommodate additional waste. The Ralston site was not used solely by Rockwell. Localbusinesses or citizens also likely disposed of various wastes at the site.

In addition to the industrial-type wastes listed above, the Ralston site was also used by Rockwellfor disposal of cyanide plating wastes (ferrocyanide salts). An undetermined number of cyanidecontainers were disposed at the Ralston site. In 1989, Rockwell removed and properly disposedof two cyanide containers. During construction of a clay cap in 1994, nine additional containersof various shapes and sizes were removed and properly disposed.

LAND USE

The northern half of the area adjacent to the Ralston site is pasture and wooded area.Surrounding this undeveloped region, residential areas occupy the western, northern, and easternboundaries. South of the railroad tracks, the land use is generally zoned commercial and lightindustrial with some isolated residences. Major commercial development generally begins southof Blairs Ferry Road.

SITE SECURITY

The Ralston site is currently surrounded by a locked chain link fence to prevent unrestrictedaccess to the property. No utilities or other permanent structures are located within the fencedRalston site boundaries. Use of the Ralston property by unauthorized personnel is forbidden, andwarning signs are posted in several areas to discourage trespassers.

AMP SOURCE: U.S.G.S. TOPOGRAPHIC QUADRANGLES.CEDAR RAPIDS NORTH AND MARION.LINN COUNTY. IOWA.

SITE LOCATION: SEC. 2. T. 84N.. R. 7W.

O 2OOO

SCALE IN FEET

VMONTGOMERY WATSON

ROCKWELL INTERNATIONALCEDAR RAPIDS, IA

SITE LOCATION MAPFIGURE 2-1

BM K3 BZ» BBE

^ UNDEVELOPED FARMLAND -

\ > •-, y I\ } ' / — ••-'$ *> /\ *• /\ <i ^- UNDEVELOPED

' ', PROPERTY BOUNDARY

CHICAGO: NORTHWESTERNTRANSPORTATION COMPANYPROPERTY-

BORROWAREA. '2

JAUES'FIAFTIS F>ROPERTf'

r-'",;: .̂,..,i K......

. LEONARD' RALSTON

PROPERTY

\r 'V X

• \ I <JAMES ~RAFTl.S> ,

PROPERTy ~\',y:

|̂ \\

8AUER WELL -•—T V ^->f/VO LONGER USED ASlOF OI\OI-93>—'O ft^~

APPROXIMATE LIMITS OF DISPOSAL AREA

DIRECTION OF CREEK FLOW

MONTGOMERY WATSON

ROCKWELL INTERNATIONALCEDAR RAPIDS. IOWA

FORMER RALSTONDISPOSAL SITE LAYOUT

FIGURE 2-2

TOPOGRAPHY

The topography of the Ralston site is characterized by steeply sloping bluffs along Dry RunCreek to the north and a railroad embankment to the south. Approximately 10 to 30 feet of reliefis associated with the steep southern banks of Dry Run Creek which form the northern boundaryof the former disposal area. South of the former disposal area, the steep slope of the railroadembankment quickly levels off to the north and forms a relatively flat area up to the south bankof Dry Run Creek. Northwest of the former disposal area, the land surface gently grades into theflood plain. Northeast of the site, the flood plain of the creek is well defined by steeply slopingbluffs and is approximately 500 feet in width. A topographic map, illustrating the localtopography in and around the site, is presented in Figure 2-3.

SURFACE WATER

Dry Run Creek is an intermittent stream which forms the northern boundary of the disposal areaof the site. The disposal area is situated on a steep cutback of the creek. Portions of the site arelocated within the 10-year flood plain of the creek with the flood area north of the creek channelparticularly susceptible to flooding. Dry Run Creek flows west to east, with discharge to IndianCreek approximately one mile downstream of the site. During heavy rainfall, overland surfacewater runoff at the site generally flows north-northwest according to site topography anddischarges into Dry Run Creek.

-•;va

'

rat

/. CONTOUR INTERVAL • 2 FEET

Z. CONTOURS REFLECT CONDITIONS PRIORTO CAP CONSTRUCTION.

MONTGOMERY WATSON

ROCKWELL INTERNATIONALCEDAR RAPIDS, IA

SITE TOPOGRAPHIC MAPFIGURE 2-3

J

SECTION 3

STORM WATER MANAGEMENT CONTROLS

RISK ASSESSMENT

Prior to installation of structural controls, the Ralston site provided three main sources for stormwater contamination including:

1. Groundwater infiltration.

2. Exposure and leaching of debris uncovered as a result of erosion of the creekcutback.

3. Surface water runoff contacting contaminated surface and subsurface soils.

STORM WATER MANAGEMENT

The potential contaminant sources are controlled through the following remedial actions:installation of a dual purpose soil vapor extraction and groundwater pump and treat system,stabilization of the south creek bank, and installation of an impermeable clay cap with vegetativecover over the former disposal area. This section will discuss the structural controls implementedto mitigate potential adverse effects to storm water quality that may be attributable to the formerdisposal site. Other potential sources of storm water contamination also will be addressed.

Dual Purpose Soil Vapor Extraction and Groundwater Pump and Treat System

A dual purpose soil vapor extraction (DVE) system, designed to extract alluvial groundwater andsoil vapor from the subsurface of the former disposal area, was installed at the Ralston site. Thespecific objectives of this removal action are as follows:

• Extract contaminated groundwater from the alluvial aquifer in and around theformer disposal site.

• Extract contaminated soil vapor from the unsaturated and vadose zones in theformer disposal area to remediate, to the extent possible, contaminated soil at thesite.

• Limit the further migration of contaminated alluvial groundwater off site.

• Lower the current groundwater table so that the DVE system can remediate thesoil in the former disposal area more effectively.

• Treat the extracted groundwater and soil vapor to concentrations sufficient tomeet approved discharge requirements.

Dry Run Creek Bank Stabilization

To minimize erosion of the south bank of Dry Run Creek, cable-stayed concrete mats wereplaced along the bank from the south edge of the creek bottom to several feet above the top ofthe bank slope. A drainage layer and geomembrane liner were placed on the bank slopeunderneath the cable-stayed concrete mats to allow the slope to drain freely and to inhibitgroundwater and surface water interaction, respectively. Details of the stabilization areillustrated in Figure 3-1.

The area along the south creek bank was cleared of trees and shrubs, and graded to allowplacement of the concrete mats. The concrete mats were constructed of 15-inch by 15-inchconcrete blocks (minimal height of 4.5 inches) joined by stainless steel cables to form 4-foot by16-foot mats. The mats are flexible and take the shape of the slope upon which they were placed.Therefore, disturbance of the subsurface during placement, which could have caused release ofcontaminants to Dry Run Creek, was minimal.

A drainage layer, consisting of a plastic mesh between two layers of geotextile fabric, was placeddirectly on the creek bank subsurface. This drainage layer will allow groundwater to escape thesubsurface following a flood or heavy rainfall thereby preventing saturated conditions that maycause slope instability and/or inhibit DVE performance.

A geomembrane liner was placed on the south creek bank, between the cable-stayed concrete andthe geotextile drainage layer, to minimize the interaction of the surface water flow into Dry RunCreek and the alluvial groundwater flow from the former disposal area. This geomembrane linerextends from just below the creek bottom to several feet above the top of the bank slope, where itis anchored in a trench. The top of the geomembrane liner was integrated with the clay capdescribed below.

Capping of the Former Disposal Area

A compacted clay cap was installed over the former disposal area to cover the contaminatedsurface soil and to prevent the potential migration of surface runoff water into the subsurface ofthe former disposal area. The cap was installed such that surface water runoff from the cap isdirected away from the former disposal area. The cap covers the former disposal area and isintegrally connected to the geomembrane liner that underlies the cabled concrete mats. Thiseffectively isolates the former disposal area from surface water infiltration and runoff.

The cap consists of 2 feet of compacted clay, with a typical maximum permeability of1x10*-7 cm/sec, overlain by 2 feet of topsoil. The topsoil layer was seeded to provide vegetativecover, so erosion of the topsoil and clay layers is minimized.

A drainage ditch was constructed around the perimeter of the capped area to direct surface wateroff and around the former disposal area and into Dry Run Creek. Terraces were included in thecap construction to reduce the flow distance across the cap and to redirect runoff from the capinto the perimeter drainage ditch.

MONTGOMERY WATSON

NOTE:

I. VETETATIVE GROWTH WLL BE MAINTAINEDON THE CAP. TERRACES AMD DRAINAGECHANNELS.

ROCKWELL INTERNATIONAL CORPORATION

SURFACE WATER FLOWAND EROSION CONTROL

FIGURE 3-1

J

Loading and Unloading Operations

As the site will remain essentially functioning as an inactive landfill, no loading and unloading ofpotential pollutants will take place. Therefore, this potential source of contamination is not anissue.

Outdoor Storage Activities

There will be no storage facilities located on the site; therefore, contamination resulting frommaterials storage is not an issue.

Outdoor Manufacturing or Processing

There will be no manufacturing or processing conducted on the site; therefore, this potentialsource of contamination is not an issue.

Dust or Particulate Generating Processes

Because the former disposal area has been capped and provided a vegetative cover, dust orparticulate generation will no longer be a potential source of contamination.

On-Site Waste Disposal Practices

There will be no additional waste disposal on the site once the clay cap is placed; therefore, thissource of contamination will not be an issue.

GOOD HOUSEKEEPING

Trash and windblown debris are to be collected and removed from the premises as necessary.

SPILL PREVENTION AND RESPONSE

Due to the nature of the site (inactive, capped landfill), potential spilling of pollutants is not anissue.

SEDIMENT AND EROSION PREVENTION

Vegetative cover has been established to provide erosion control in all designated areas disturbedduring installation and construction of the various elements of the site remediation including, butnot limited to, the capped area and associated drainage ditches and terraces, and embankmentsabove the cable-stayed concrete mats.

Maintenance and repairs to the vegetative cover shall be completed in areas of rill erosion with adepth of greater than 3 inches and width greater than 4 inches. Repairs shall be completed onindividual bare areas greater than 1 square yard or total bare areas exceeding 2 percent of theentire vegetative area.

EMPLOYEE TRAINING

Because the site is an inactive landfill, employee training issues are not relevant.

PREVENTIVE MAINTENANCE

Because there are no mechanical systems associated with storm water management at the site,preventive maintenance issues are not relevant.

MANAGEMENT OF RUNOFF

Grassed drainage channels and terraces have been constructed to divert surface water off andaround the former disposal area.

RECORD KEEPING

All records of environmental permits, hazardous waste manifests, etc. will be kept in appropriatelocations at 400 Collins Road in Cedar Rapids.

NONSTORM DISCHARGES

Based upon visual observation and the nature of operation (inactive landfill), there are no sourcesof nonstorm water discharges associated with the site.

VISUAL INSPECTION

Visual inspections of the site will be conducted according to the IDNR General Permit No. 1Part HI.C.4.c.(4) as the site will exist as an inactive site. In accordance with the aforementionedreference, visual inspections will be conducted at least once per three-year period.

Typically, the inspections of the Ralston site will include examination of the clay cap and cable-stayed concrete mat areas in addition to any areas previously identified as potential sources ofstorm water contamination. Potential erosion areas and vegetative cover will also be examined.

Following each visual inspection, a brief report will be prepared documenting the date, personsconducting the inspection, areas inspected, identified areas of concern, preliminary actions takenand whether the items of concern are newly identified or recurring problems. This report will beretained by Rockwell with the SWPPP.

If a visual inspection finds that remedial or preventive action is warranted, mitigation efforts willbe coordinated by Rockwell personnel.

SECTION 4

STORM WATER SAMPLING

Part V.B.3 of General Permit No. 1 specifies monitoring requirements for any active or inactivelandfills that have not installed a stabilized final cover. Because the Ralston site has a stabilizedfinal cover, the site is exempt from such monitoring requirements.

SECTION 5

ADMINISTRATIVE PROCEDURES

In order to document any changes on the site that would have significant effects to storm waterquality, record keeping and reporting requirements, administrative procedures associated withthis SWPPP are included.

Copies of this SWPPP, and reports required will be kept for at least 3 years. The plan will bereviewed annually and will be revised if needed. Rockwell will reapply for new permits asnecessary according to Part II.E of General Permit No. 1. Reporting of any incidence ofnoncompliance will take place according to Part V.C of General Permit No. 1.

The following individual shall be responsible for implementing, maintaining and revising thisSWPPP.

Name ______________________

Title ______________________

Date ______________________

SWPPP INSPECTION AND RESPONSE RECORD

Date.

Inspection Performed By:

Certification: I have reviewed this inspection record and will provide the necessary resourcesand manpower to modify the SWPPP and implement the appropriate changes.

Observations / Actions Taken / Follow-up (Use Additional Pages if Necessary):

SWPPP INSPECTION AND RESPONSE RECORD

Date

Inspection Performed By:

Certification: I have reviewed this inspection record and will provide the necessary resourcesand manpower to modify the SWPPP and implement the appropriate changes.

Observations / Actions Taken / Follow-up (Use Additional Pages if Necessary):

SWPPP INSPECTION AND RESPONSE RECORD

Date

Inspection Performed By:

Certification: I have reviewed this inspection record and will provide the necessary resourcesand manpower to modify the SWPPP and implement the appropriate changes.

Observations / Actions Taken / Follow-up (Use Additional Pages if Necessary):

SWPPP INSPECTION AND RESPONSE RECORD

Date_

Inspection Performed By:

Certification: I have reviewed this inspection record and will provide the necessary resourcesand manpower to modify the SWPPP and implement the appropriate changes.

Observations / Actions Taken / Follow-up (Use Additional Pages if Necessary):

SWPPP INSPECTION AND RESPONSE RECORD

Date

Inspection Performed By:

Certification: I have reviewed this inspection record and will provide the necessary resourcesand manpower to modify the SWPPP and implement the appropriate changes.

Observations / Actions Taken / Follow-up (Use Additional Pages if Necessary):