The Dow Chemical Company · The Dow Chemical Company-Michigan Operations Reach M Monitoring Plan...

______________________________________________________________________ he Dow Chemical Company T Midland, MI 48674 December 31, 2009 Mr. Al Taylor Geology Specialist Hazardous Waste Technical Support Unit Waste and Hazardous Materials Division Michigan Department of Environmental Quality Lansing, MI 48909 Subject: Submittal of Monitoring Plan for the Pilot River Bank Stabilization Projects. Dear Mr. Taylor, Please find attached the Monitoring Plan for the Pilot River Bank Stabilization Projects. This monitoring plan replaces the plan submitted as the Post Construction Monitoring Plans for the Upper Reach M Pilot River Bank Erosion Stabilization Project (December 5, 2008) and also addresses the additional monitoring requirements outlined in the Work Plan to Implement Pilot River Bank Stabilization Projects on the Tittabawassee River dated June 16, 2008. Monitoring of the Pilot River Bank Stabilization Projects will be conducted for the required 5 years and reported annually. Please feel free to call me if you have any questions regarding the information on this Final Report. Sincerely,

Todd Konechne The Dow Chemical Company 1790 Building Midland, MI 48674 Cc: Greg Cochran Steve Lucas

Mary Logan

The Dow Chemical Company Reach M Monitoring Plan

December 31, 2009

Prepared by URS Corporation

The Dow Chemical Company-Michigan Operations Reach M Monitoring Plan

Table of Contents

1.0 Introduction..............................................................................................................1 1.1 Background..................................................................................................2 1.2 Site Locations and Completed Pilot Activities ............................................2 1.2.1 Upper Reach M................................................................................2 1.2.2 Lower Reach M................................................................................3 1.2.3 Reach O............................................................................................5 1.2.4 Reach Q............................................................................................5 1.2.5 Reach N............................................................................................5 2.0 Monitoring Plan Overview ......................................................................................7 2.1 Overall site Condition ..................................................................................7 2.2 Vegetation Monitoring – Forbs, Grasses, Trees, and Shrubs ......................8 2.3 Invasive Species Monitoring........................................................................9 2.4 Green Wall Structural Monitoring Activities ..............................................9 2.4.1 Structural Integrity Monitoring......................................................10 2.4.2 Detailed Component monitoring.................................................10 3.0 River Impacts Monitoring Activities .....................................................................12 4.0 Reporting ..............................................................................................................14

Tables

Table 1 ........................................Monitoring Plan – Pilot River Bank Stabilization Project

Appendices

Appendix A....................................................................Green Wall System Analysis Form

Figures

Figure 1 .................................................................................................. Site Locations Map


1.0 Introduction

This monitoring plan replaces the plan submitted as the Post Construction Monitoring

Plans for the Upper Reach M Pilot River Bank Erosion Stabilization Project (December

5, 2008) and also addresses the additional monitoring requirements outlined in the Work

Plan to Implement Pilot River Bank Stabilization Projects on the Tittabawassee River

dated June 16, 2008.

This plan addresses the monitoring requirements for the Tittabawassee River where river

bank erosion/stabilization pilot projects were conducted along with requested monitoring

at two additional locations as controls where no erosion pilot activities were

implemented:

• Upper Reach M - Approximately 900 linear feet of bank stabilization that was

constructed from August to October 2008 under Michigan Department of

Environmental Quality (MDEQ) Permit No. 08-56-0047-P, dated September 5,

2008;

• Lower Reach M - Approximately 700 feet of this river section where several

different pilot technologies were implemented;

• Reach O - Three areas along the river bank that were restored after the completion

of the July - November 2007 Reach O removal activities;

• Reach Q - An area of Reach Q with no erosion controls having elevated dioxin and

furan levels (as determined by Toxic Equivalency values (TEQs)) and a moderate

Bank Erosion Hazard Index (BEHI, which quantifies bank stability factors based on

bank geometry (height and angle), surface protection, vegetation rooting density,

and vegetation rooting depth); and

• Reach N - The southwest riverbank area (reference stations 300+00 to 304+00)

having elevated TEQs and an elevated BEHI screening value with no erosion

controls. This area was the focus of initial point cloud imaging surveys conducted

in January 2008, as reported by ENVIRON and LimnoTech in the River Bank

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Stabilization Pilot Corrective Action Project Report for the Tittabawassee River,

Michigan April 1 2008.

1.1 Background

On April 16, 2008, the MDEQ submitted a letter requiring The Dow Chemical Company

(Dow) to prepare a work plan to implement a Pilot Corrective Action to address eroding

banks of the Tittabawassee River. The plan needed to prioritize and propose at least three

areas where bank erosion stabilization pilot projects would be implemented in 2008. One

of the goals of the pilot projects would be to evaluate the effectiveness of bank

stabilization technologies for further use along the Tittabawassee River. The letter also

referenced the importance to evaluate technologies that have a “soft footprint”. In

response, Dow submitted a work plan on June 16, 2008 selecting Upper and Lower

Reach M and Reach O as pilot project areas. Also included in the Work Plan was the

monitoring of Reach Q and Reach N areas.

1.2 Site Locations and Completed Pilot Activities

The following locations were included in the stabilization pilot projects and are depicted

in Figure 1:

1.2.1 Upper Reach M

Upper Reach M of the Tittabawassee River is located in Midland County, Ingersoll

Township, Michigan approximately three miles downstream from Dow’s Midland Plant.

Reach M begins at the Bailey Bridge on Smith's Crossing Road and extends

approximately 2,400 feet down river. The selected pilot project area of Reach M is on

the northeast bank of the river between Reference Stations 269+00 and 285+00. Upper

Reach M extends from Station 269+00 to Station 278+00 (approximately 900 feet).

The river bank restoration of Upper Reach M consisted of engineered bank stabilization

using an Envirolok™ wall. The site activities included tree removal, excavation and

reshaping the river bank, installation of the Envirolok™ bags, and live planting and

seeding.

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Specifically:

• The existing Upper Reach M riverbank was excavated to a more stable slope from

the existing slope grade ranging from 1.5: 1 to 1: 1. The existing slope was over-

excavated approximately six feet to accommodate the installation of geogrid tie-

back stabilization material that was installed in layers, and the “green wall

system”;

• After excavation, the exposed soil was covered with an encapsulated bag system

filled with engineered soil. Sand backfill was placed immediately behind the

encapsulated wall in combination with drainage tile. The purpose of the drainage

system was to alleviate potential hydraulic pressure from behind the constructed

wall that could compromise its structural integrity;

• Following installation of the green wall system, the reconstructed bank area and

disturbed upland areas were re-vegetated with native seed, live plants, and trees.

Three distinct vegetation types (emergent, mesic and upland savannah) were

planted at different locations on the bank based on soil hydrology.

1.2.2 Lower Reach M

Lower Reach M is an approximate 700 foot section of river starting at upstream

Reference Station 278+00, and extending down river to Reference Station 285+00.

Lower Reach M was considered to be at a lesser risk of erosion due to more gradual

sloping of the banks and less height as compared to those in the Upper Reach M area.

Seven restoration technologies were pilot-tested across the Lower Reach M area. The

activities conducted for these pilots were generally similar in bank preparation and had

little overall site impact. Two of the goals of the pilot projects were to minimize

disturbance of the existing conditions found at the site (leaving behind as minimal a

footprint as possible when site activities were completed) and to reduce surface erosion

of the river bank and promote native vegetation growth. In the entire area of Lower

Reach M, canopy management was implemented to increase the sun light to the bank

3


area. This work was performed in the winter when the ground was frozen and covered

with snow to minimize ground disturbances. The piloted technologies included:

• Construction of an Envirolok™ bag system without extensive reshaping of the river

bank to protect existing, exposed tree root systems, and river bank restoration;

• Placement of a topsoil/compost-filled, fabric quilt on the existing river bank. Before

seeding the quilted area, a light layer of compost was sprayed on top of the quilt to

give the seed a good germination bed;

• Hydro seeding a native vegetation mix of forbs and grasses over the existing ground

vegetation found on the bank. The hydro seed was applied to the existing

conditions of the bank to determine how well the seed could compete and establish

alongside the existing vegetation;

• Placement of Geoweb® directly into the river bank and filling with topsoil. After

the soil was firmly packed into each Geoweb® cell, a layer of hydro seed

containing native forbs and grasses was applied to the surface and then covered

with an erosion protection coconut blanket;

• Installation of coconut blanket over cleared bank face. On the prepared surface,

hydro seed consisting of native forbs and grasses was applied followed by coconut

blanketing that was anchored into the bank face. At the toe, the coconut blanket

was weighted down with 4” natural stone. In another portion of the same area,

coconut blanket was placed over existing vegetation to determine how well it could

compete and penetrate the coconut blanket;

• Canopy management to trim or remove excess trees and increase light levels on the

river bank face to enhance growth of existing vegetation. Canopy management was

applied with all other treatments and on its own with no additional treatment in one

location; and

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• Placement of nursery-grown sod on the existing river bank subgrade to establish

vegetation. The sod was grown for eight weeks, shipped to the site and then

installed in 3 x 15 foot rolls.

1.2.3 Reach O

Reach O is a section of the Tittabawassee River located in Midland and Saginaw

Counties, bounded by upstream Reference Station 320+00 and the down stream

Reference Station 335+50. Three areas of the river bank used as access locations were

disturbed during the late summer and fall 2007 removal activities. The river bank was

reconstructed in the fall of 2007 with some additional maintenance performed in July

2008. During the initial restoration, tree logs were used at two of the access ramps to

help with the erosion control measures. After several flood events occurred during the

first spring season, several of the logs were lifted out of place. As a remedy, the

Envirolok™ bag systems was used for reconstruction and erosion control measures to fix

and augment the previously installed erosion control measures at the access areas.

1.2.4 Reach Q

Reach Q is a section of the Tittabawassee River located in Saginaw County extending

from Reference Station 358+00 to downstream Reference Station 377+50 and having

elevated dioxin and furan TEQ levels and a moderate BEHI screening value. Reach Q is

a control area and will be evaluated through a range of monitoring approaches useful for

tracking long-term river bank stability and natural changes to river bank conditions over

time. Monitoring approaches will include BEHI assessment, bank and bed pins, point

cloud surveys, multi-beam bathymetry and vegetation cover. No erosion controls were

implemented in Reach Q as part of the Pilot Project.

1.2.5 Reach N

Reach N is a section of the Tittabawassee River located in Saginaw County starting at

Reference Station 286+00 and extending downstream to Reference Station 320+00.

Reach N also contains an area with elevated TEQ and BEHI screening values, where no

erosion controls were implemented as part of the pilot project. The southwest riverbank

5


area extending from Reference Station 300+00 to Reference Station 304+00 will also be

evaluated through a range of monitoring approaches useful for tracking long-term river

bank stability and natural changes to river bank conditions over time. Monitoring

approaches will include BEHI assessment, bank and bed pins, point cloud surveys, multi-

beam bathymetry and vegetation cover.

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2.0 Monitoring Plan Overview

This monitoring plan was prepared to outline the procedures and protocols that will be

used to monitor the implemented pilot technologies and restoration activities conducted

at Reaches M and O; the bank stability enhancements within Reaches Q and N; and the

potential impacts to the Tittabawassee River from the river bank modifications made

during pilot technology construction activities.

The plan includes procedures for monitoring overall site conditions, restored vegetation

(establishment, diversity and basal cover), invasive species, structural and component

monitoring of the Envirolok™ wall, and river monitoring to evaluate impacts to the

Tittabawassee River. The plan also includes a reporting schedule. Table 1 provides a

summary of the monitoring activities to be performed at Upper and Lower Reach M,

Reach N, Reach O and Reach Q.

2.1 Overall Site Condition Monitoring

Monitoring of overall site conditions at Reach M and O will be conducted for a period of

five years, with detailed evaluations being conducted twice per season between the

months of April and October. Any area of exposed soil that is greater than one square

meter will be mapped and photo-documented. Observations will specifically note

damage due to flooding, ice, animals or any other disturbances.

Visual observations will include assessing the native plants, grasses, planted trees and

shrubs for growth and general health. Documentation of any changes to overall site

conditions will include the establishment of 360-degree photo points to provide an

overview of the river bank face and floodplain areas. These points will be mapped with

GPS coordinates to ensure that they can be easily relocated, and added to the existing site

features map that will be included in the annual monitoring report.

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2.2 Vegetation Monitoring – Forbs, Grasses, Trees and Shrubs

Site vegetation monitoring with detailed evaluations of Reaches M and O will be

conducted twice per season between the months of April and October. An overall

evaluation will be made with an annual comparison of the sites’ re-vegetation success in

terms of monitoring density and diversity of grasses, forbs, trees and shrubs. Two distinct

areas will be monitored:

• The reconstructed river bank areas; and

• The disturbed upland areas between the top of the reconstructed river bank and the

existing undisturbed forested area, including areas that were disturbed during site

activities to provide access to the river bank.

A series of monitoring transects located approximately 150 to 200 feet apart will be

established. These transects will be located perpendicular to the river across both the

river bank and upland areas to monitor forbs and grasses. A permanent marker will be

placed at each end of the transect. Each transect will include random sampling plots

and will be approximately one square meter in size. Along the river bank area, the

different types of vegetation (emergent, mesic and upland savannah) will be included in

at least one monitoring plot.

Species diversity of the site and percent cover within the one square meter plots will be

observed and documented. Photos of the monitored plots will also be taken during each

monitoring event to document vegetation coverage.

The monitoring plot photos and data will be used to provide comparisons over time of

the change in vegetation density and diversity. In addition to the vegetation density and

diversity, the overall site will be inspected for any specific areas lacking vegetation that

may promote erosion. Visual observation of the restoration areas for signs of erosion and

lack of vegetation will be completed during the routine monitoring events. Areas that

show erosion or a lack of vegetation cover will be identified, documented, and

8


specifically inspected during the subsequent monitoring event to determine if any

corrective measures are necessary.

Monitoring of trees and shrubs will be performed on approximately 30 percent of the

species planted as part of the restoration in the upland area on Upper Reach M. The

randomly selected trees and shrubs will be tagged, numbered and mapped with GPS

coordinates, and added to the site features map. To monitor the success of the tress and

shrubs planted within the river bank and upland areas, visual observations and

measurements such as height and girth will be conducted to document the growth and

general health of the entire site. The observations will focus on damage caused by

flooding, ice, animals or any other disturbances. Species survival rate will be

documented for the tree and shrubs that are monitored.

2.3 Invasive Species Monitoring

Any noxious weeds and/or invasive species that may affect or inhibit the native species

diversity within the limits of the river bank and upland areas will also be monitored

during the five year program. Some acceptance of these species may be permitted if they

beneficially reduce exposed areas of soil or promote bank stability through deep rooting

or other beneficial factors. A general assessment of noxious weeds and invasive species

will be documented in each annual monitoring report.

2.4 Structural and Component Monitoring of the Green Wall

The Upper and Lower Reach M and Reach O Pilot Projects utilized variations of the

Envirolok™ systems in the reconstruction/restoration of the river banks in these areas. In

Upper reach M, the entirety of the river bank pilot incorporated the green wall system.

Accordingly, detailed monitoring of the Upper Reach M green wall’s structural

component integrity will be conducted for a period of five years. The Lower Reach M

and Reach O areas that utilized small portions of the Envirolok™ system will be

monitored consistent with the other technologies used in the pilot.

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2.4.1 Structural Integrity Monitoring

Since the constructed green wall within Upper Reach M involved restoring the entire

river bank with an Envirolok™ bag system, structural integrity monitoring to track

potential movement of the wall through GPS surveying technology will be conducted

within the project area once a year during low water season, defined as elevations of 586

feet or lower at the site (anticipated to be during late summer). The monitoring

information generated from these inspections will also be included in the annual

monitoring report. Along with the GPS tracking, visual inspections will be conducted to

observe the native soil toe, soft bench and engineered toe foundation.

The GPS tracking survey will consist of establishing permanent locaters on the green

wall adjacent to the one square meter plots discussed in Section 2.2. There will be at

least three permanent locaters for each perpendicular monitoring transect. During the

monitoring event, the GPS coordinates will be identified for each locator and recorded.

This data will be compiled and compared to previous monitoring data for any

indications of wall movement. The coordinate data will be monitored for five years. If

significant wall movement is identified at one of the locations, additional monitoring

and inspections may be conducted to determine if any corrective actions are necessary,

The GPS Tracking results and visual inspections will be documented on the Green Wall

System Structural Analysis Form provided in Appendix A.

2.4.2 Detailed Component monitoring

Detailed component monitoring will consist of visual inspections of the green wall

system components’ condition and integrity. The following items will be evaluated and

documented as part of this monitoring:

• Extent of UV protection provided by vegetation;

• Bag material condition and integrity;

• Geogrid condition and integrity, and

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• Bag encapsulation conditions.

The integrity of the green wall and its components are greatly dependent on vegetation

success, therefore component monitoring will be conducted in conjunction with the

vegetation monitoring program. The component monitoring will also incorporate the

same transects used for the vegetation monitoring activity. Both a transect-by-transect

and overall visual inspection of the green wall will be conducted to look for any areas

where the wall components may have been compromised. Areas showing a deficient

amount of vegetation or presenting signs of potential concern will be documented. The

visual observations for the component monitoring will be documented on the Green

Wall System Component Analysis Form included as Appendix A. Photo documentation

of the green wall will be included during the monitoring event.

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3.0 River Impact Monitoring Activities

Potential river impacts and geomorphologic changes resulting from the pilot projects

will also be evaluated during the monitoring program. These elements were originally

part of the GeoMorph Site Characterization activities conducted in accordance with the

2008 GeoMorph Sampling and Analysis Plan: Tittabawassee River, Midland Michigan.

and 2008 Quality Assurance Project Plan (QAPP): GeoMorph Investigation,

Tittabawassee River, Midland Michigan (collectively known as the "GeoMorph Work

Plan") approved by the MDEQ on July 10, 2008. The Final GeoMorph Site

Characterization Report was submitted to the MDEQ and USEPA on June 15, 2009.

Banks, over-bank surfaces, and the river channel bed were systematically monitored

along the entire Tittabawassee River as part of the overall site characterization effort. In

2008, a full Rosgen-style Watershed Assessment of River Stability & Sediment Supply

(WARSSS) was initiated as part of this study. The WARSSS includes an analysis of the

BEHI, which quantifies bank stability factors based on bank geometry (height and angle),

surface protection, vegetation rooting density, and vegetation rooting depth. A report on

the WARSSS Assessment was included in Volume 3 of the June 2009 Final Site

Characterization Report. The geomorphologic components pertinent to this Monitoring

Plan are listed below.

Bank Stability Measurements

• Bank and over-bank erosion/deposition pins with precision land survey at

specified transects; and

• Continuous, precision laser point cloud survey of banks under low flow

river conditions for differential surface analysis.

Bed Stability Measurements

• Precision, continuous multi-beam bathymetry under high flow conditions for

differential surface analysis; and

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• Erosion/deposition bed pins and chains with precision land survey at

specified transects.

For those measurements taken on a transect basis, such transects have been located

upstream of the bank stabilization pilot in Reach L, within the Reach M pilot project area

itself, in Reaches N and Q, and downstream of the pilot area.

Procedures for collecting and evaluating these measurements are given in the following

sections of the 2008 Tittabawassee River Quality Assurance Project Plan (QAPP) (Ann

Arbor Technical Services, Inc., July 2008):

• Appendix CC-2: Installation and Monitoring of In-Channel (Bed) Erosion Pins and

Chains; and

• Appendix CC-3: Installation and Monitoring of Bank/Overbank Erosion Pins.

Information from each line of evidence will be reviewed annually to evaluate bed and

bank stability, as well as overall channel stability.

13


4.0 Reporting

An annual monitoring report will be prepared and submitted to the MDEQ by December

31 of each year. The monitoring activities contained in this plan will be conducted for a

period of five years. Relevant findings from bank and bed stability monitoring will be

summarized in the annual monitoring report for the piloted areas.

14


Tables


Table 1 Monitoring Plan – Pilot River Bank Stabilization Project Tittabawassee River December 2009

Area Upper Reach M Lower Reach M Reach O Reach Q Reach N

Overall Site Conditions X X X Detailed Vegetative Monitoring X X X

Photographic Documentation X X X

Component Monitoring Environlok Bags X

Structural Monitoring Environlok Bags X

Bed Stability Measurements X X X X X

Bank Stability Measurements X X X X X


Appendix A

Green Wall System Analysis Form

Transect 1 Transect 2 Transect 3 Transect 4 Transect 5

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15UV Protection

Bench Section

Wall Section

Bag Material

Bench Section

Wall Section

Geogrid

Bag Encapsulation

Bag Encapsulation Failure Mode

Bag Encapsulation Risk Analysis

Green Wall System Component Analysis1 = Best 5 = Failure

Key NotesBag Material

(Best) 1 Material looks like new, shows no signs of black color loss and is pubescent2 Bag material is less pubescent and lighter in color (black/grey)3 Bag has become fragile, light in color (grey) and lacks pubescence4 Bag is worn looking, exposing engineered soil

(Worst) 5 Face of bag has become tattered and worn off exposing engineered soil and roots

Bag Material (Best) 1 Material looks like new, shows no signs of black color loss and is pubescent

2 Bag material is less pubescent and lighter in color (black/grey)3 Bag has become fragile, light in color (grey) and lacks pubescence4 Bag is worn looking, exposing engineered soil

(Worst) 5 Face of bag has become tattered and worn off exposing engineered soil and roots

Geogrid(Best) 1 Material looks like new, shows no signs of coating cracks or flaking

2 Material coating is cracking or flaking3 Coating has exposed inner nylon yarn4 Coating has long areas of exposed high tensile yarn

(Worst) 5 Material is uncoated exposing nearly all the nylon and unraveling coming away from the bag

Bag (Be Bags appear full w/o holesEncapsulation Bag has holes but has little volume loss

3 Bag is partially full and has hydraulically piped out the bag fill but is maintaining its area4 Bag has significant loss of volume and has allowed next course to settle

(Worst) 5 Bag is nearly empty or missing and next course has collapsed into the void

Bag 1 Smooth cut or slice through bagEncapsulation a IceFailure Mode b Mower

c Vandalismd Other

2a Debrisb Treesc Animalsc Other

3a Ultraviolet lightb Firec Near heat sourced Other

Bag (Be Roots occupy nearly every cubic inch of soil preventing hydraulic piping and nearly no collapse of above layerEncapsulation Root mass adequate but hydraulic piping is occurring and may cause settlingRisk Analysis 3Minimal root mass in bag. Hydraulically piping engineered bag fill. Bags in above course settling

4 Bag has significant loss of volume and has allowed next course to settle and bag is suspended(Worst) 5 Bag is nearly empty or missing and next course has collapsed into the void

Tear or ripped appearance

Bag face is gone or bag is brittle

Bench Section

Wall Section

Wall Section


Figures

N. River Rd.

Midland Rd.

Smith

s Cro

ssing

Rd.

Rogers Rd.

N. Saginaw Rd.

Buck Rd.

N. O

rr Rd

.

PQ

NO

LM

MN

QR

OP

263+00265+00

267+00269+00

271+00273+00

275+00277+00

279+50

287+00290+50

294+50298+50

302+50305+00

307+50309+50

311+50313+50

315+50

321+50324+50

327+50

336+00339+50

343+50347+00

350+50

359+00361+50

364+50366+50

369+00371+50

378+00

Figure 1Tittabawassee River

StationsReachRoads

q0 500 1,000250 Feet

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