ADDENDUM #1

February 6, 2015

RFP 15-03 WOLFTRAP CREEK STREAM RESTORATION

******ATTENTION BIDDERS******

(To be completed and returned with bid response)

A request was made that the Stormwater Local Assistance (SLAF) grant package and the supporting documentation be made available to interested firms. Those documents are attached to this Addendum. ALL OTHER TERMS, CONDITIONS, AND SPECIFICATIONS SHALL REMAIN THE SAME. A copy of this signed addendum must accompany your response as an acknowledgment of its receipt:

NAME AND ADDRESS OF FIRM: ______________________________________________ ______________________________________________ ______________________________________________ ______________________________________________ PHONE #:__________________________ EMAIL: ___________________________ NAME OF AUTHORIZED REPRESENTATIVE: ______________________________________________ Please Print SIGNATURE: __________________________________ DATE: ________________

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Wolftrap Creek/Difficult Run - Stream Restoration Grant Application Stormwater Local Assistance Fund 2014

Town of Vienna Grant Application for a Stream Restoration Project to the 2014 Stormwater Local

Assistance Fund

Stream Restoration Grant Proposal Wolftrap Creek – Difficult Run

Vienna VA

Page 1 of 13

Contents A: Background ............................................................................................................................................... 2

B: Environmental Benefit .............................................................................................................................. 4

C: Statement of Need .................................................................................................................................... 5

Condition of the Stream Sections ............................................................................................................. 5

TP (Total Phosphorus) ............................................................................................................................... 6

Stream Restoration Description ................................................................................................................ 7

Maintenance ............................................................................................................................................. 7

D: Grant Application Summary ..................................................................................................................... 8

I. POLLUTION REDUCTION ................................................................................................................... 8

II. COST EFFECTIVENESS ........................................................................................................................ 8

III. IMPAIRED WATER BODIES ............................................................................................................ 8

IV. FISCAL STRESS ............................................................................................................................... 8

V. READINESS TO PROCEED ................................................................................................................... 9

VI. PHASE II (SMALL) MS4 ................................................................................................................... 9

E: Closing ....................................................................................................................................................... 9

Figure 1 – Location Map and Extents of Proposed Project ........................................................................... 4

Figure 2 - Section 1 – 3’-4’' eroded bank ...................................................................................................... 5

Figure 3 - Stream Condition Types ................................................................................................................ 5

Figure 4 – Sinuosity Example ........................................................................................................................ 5

Figure 5– Difficult Run Channel Evolution Model Map................................................................................. 5

Figure 6 – Difficult Run Sub Watershed Modeling Results ........................................................................... 6

file://Nas-th-2/pw-th-shared%20folder/0%20Seth%20Haffner/Water%20%20Sewer%20and%20Storm/0%20-%20Storm%20Related/Streams/Stream%20Walks%20-%20POssible%20SLAF%20Grant%20Projects/Wolftrap%20Extension/Narrative%20-%20Draft.docx%23_Toc401665506file://Nas-th-2/pw-th-shared%20folder/0%20Seth%20Haffner/Water%20%20Sewer%20and%20Storm/0%20-%20Storm%20Related/Streams/Stream%20Walks%20-%20POssible%20SLAF%20Grant%20Projects/Wolftrap%20Extension/Narrative%20-%20Draft.docx%23_Toc401665507file://Nas-th-2/pw-th-shared%20folder/0%20Seth%20Haffner/Water%20%20Sewer%20and%20Storm/0%20-%20Storm%20Related/Streams/Stream%20Walks%20-%20POssible%20SLAF%20Grant%20Projects/Wolftrap%20Extension/Narrative%20-%20Draft.docx%23_Toc401665508file://Nas-th-2/pw-th-shared%20folder/0%20Seth%20Haffner/Water%20%20Sewer%20and%20Storm/0%20-%20Storm%20Related/Streams/Stream%20Walks%20-%20POssible%20SLAF%20Grant%20Projects/Wolftrap%20Extension/Narrative%20-%20Draft.docx%23_Toc401665509file://Nas-th-2/pw-th-shared%20folder/0%20Seth%20Haffner/Water%20%20Sewer%20and%20Storm/0%20-%20Storm%20Related/Streams/Stream%20Walks%20-%20POssible%20SLAF%20Grant%20Projects/Wolftrap%20Extension/Narrative%20-%20Draft.docx%23_Toc401665510file://Nas-th-2/pw-th-shared%20folder/0%20Seth%20Haffner/Water%20%20Sewer%20and%20Storm/0%20-%20Storm%20Related/Streams/Stream%20Walks%20-%20POssible%20SLAF%20Grant%20Projects/Wolftrap%20Extension/Narrative%20-%20Draft.docx%23_Toc401665511

Stream Restoration Grant Proposal Wolftrap Creek – Difficult Run

Vienna VA

Page 2 of 13

A: Background:

The Town of Vienna is located approximately 15 miles west of Washington D.C. and is called

home by approximately 16,000 residents. With a geographic area of slightly over 4 square miles the

Town is one of a handful of incorporated areas within Fairfax County. The Town was primarily

developed during the 1950s and 60s without the environmental benefits of Stormwater Management and

Water Quality Treatment. Further subdivision development in the 1980’s throughout the Town of Vienna

increased impervious areas, enclosed tributaries, straightened streams, removed riparian buffers and

steepened stream banks to allow more homes to be built. Recently the Town has experienced a re-

development boom leading to a further increase in impervious surfaces and a further burden on the

receiving water courses. Predictably the receiving streams and channels have experienced incision,

erosion and widening in response to the increase in water quantity as a result of 50 plus years of

development. Within Vienna’s four plus square miles is the watershed for the Wolftrap Creek section of

the Difficult Run watershed and subject of this application.

The Wolftrap Creek section this proposed project will impact is an unassessed portion

categorized as a 3A in the Virginia 2012 Impaired Waters – 303(d) category list. However other assessed

section are listed as type 5 (the most severe impairments). Additionally the Wolftrap Creek flows to the

Potomac and the Potomac is under a TDML. Still, this section shares many of the same issues of assessed

sections. Additionally, this section is just upstream of a previous restoration project on Wolftrap. The

issues affecting this section are the same as the downstream section previous restored, the previously

restored section is described as follows from a Fairfax SlideShare presentation:

“Before restoration, the stream and the natural habitat were degraded. Poor water quality

and loss of the natural habitat are hallmarks of a poor environment… Uncontrolled stormwater

runoff flowed through the stream and eroded the banks exposing tree roots. Trees were falling

which created a safety hazard. Sediment was deposited in the streambed by stormwater runoff.

Some aquatic animals raise their young in streambeds. Sediment covers the streambed and kills

aquatic animals living there. Undercut stream banks, unbalanced sediment transport and fallen

trees, demonstrate the “before” appearance of the area. (County, 2013)1

Municipal maintenance funds are only available for occasional dredging of sediment but not for

corrective action to prevent the erosion and to naturally stabilize the stream. Stream bank armoring and

dredging have been used for years as the standard repair method by Vienna stream maintenance crews.

Funding is tight; therefore, problems are not addressed preventatively, but only in reactive mode. This

project will show local staff and residents the practical aspects of correcting the problem of stream bank

erosion before sediment must be dredged from the stream. As it ages, the stabilization of the problem

area will demonstrate how carefully preparing for natural restoration is cheaper in the long run with the

elimination of costly dredging. This project will extend closer to the ultimate headwaters and additional

1 From :Wolftrap Stream Restoration in Wildwood Park, Vienna, Virginia, slideshow

http://www.slideshare.net/fairfaxcounty/final-approved-wolftrap-stream-pp-for-slideshare-october-22-2013

Stream Restoration Grant Proposal Wolftrap Creek – Difficult Run

Vienna VA

Page 3 of 13

action on this stream will help maintain the previously restored downstream section by reducing the

sediment load.

In 2013 additional regulation in response to the continuing challenges faced by the Chesapeake

Bay went into effect and the Town of Vienna, as a MS4 permitee, will experience additional requirements

relating to the water quality in its streams. The town has executed a cooperative agreement with Fairfax

County to share responsibility for implementing a joint Chesapeake Bay TDML Action Plan. As a

function of these requirements and the cooperative agreement with the Fairfax County the amount of

Phosphorus, Nitrogen and Total Suspended Solids will need to be reduced. Vienna, in conjunction with

working with the Fairfax County, has a role and responsibility in meeting these requirements. Formal

correspondence with Fairfax County has indicated available construction funding for the restoration to

constitute the matching funds required for the grant, (Appendix C, Letter from Fairfax County). This

application also makes multiple references to Fairfax’s Difficult Run Watershed Management Plan. This

plan describes the needs and requirements for the future of the watershed, and a path to meeting the

requirements of the coming regulations.

Stream Restoration Grant Proposal Wolftrap Creek – Difficult Run

Vienna VA

Page 4 of 13

B: Environmental Benefit

The primary aim and quantified requirement in meeting the grant application standards is

establishing the amount of Total Prosperous to be removed as a result of the proposed project. This

project proposes to stabilize approximately 1,020 feet of stream bank within the borders of the town of

Vienna, see figure 1.

The section for restoration is in the Wolftrap Creek in the Difficult Run watershed just upstream

from a previously restored section of stream. This section is located entirely on Town property and is

close to the headwater of the stream. As a result of being situated in the headwaters, all downstream

sections will benefit from stabilization and restoration that takes place in the upper reaches. The erosion

of stream banks causes suspended solids, which may be laden with phosphorus, to be suspended in runoff.

Additionally, the restoration of stream banks provides a means of pretreatment for runoff and removal of

phosphorus prior to reaching the stream. As outlined in the grant application a credit of 0.068 lbs per

linear foot of restored stream is credited for stream restoration projects.

o Approximately 1,020 linear feet of restored Stream: At 0.068 lbs/ft = 69.36 lbs of removed Phosphorus

Phosphorus amounts were tabulated utilizing the grant application credited rate of 0.068 lbs/ft,

methodology for calculating total phosphorus reduction, Attachment A of the Stormwater Local

Assistance Fund grant application.

Figure 1 – Location Map and Extents of Proposed Project

Stream Restoration Grant Proposal Wolftrap Creek – Difficult Run

Vienna VA

Page 5 of 13

C: Statement of Need

Condition of the Stream SectionsThe current condition of the stream

sections have been evaluated onsite and

photographed as shown to the right, additional

photographs are included in Appendix A. In

addition to the site visits and photographs taken, the

Fairfax County Watershed Plan for the Difficult

Run was reviewed for insight into the phosphorus

loads arising from the drainage areas. Figure 2 to

the right shows the degree of incision and erosion

along the banks. While walking the stream several

areas of 3 to 4’ high eroded banks are clearly

visible. In many of these areas existing trees have

been undermined and overturned. Figure 4 to the

right shows the degree of sinuosity in the stream,

again a common sight along this stream. As the

stream turns there is too much volume and velocity

for the existing soils resulting in erosion and loss of

available water quality storage treatment in fringe

flood plains. The condition of the stream appears

to be a Type III as described by figure 3 below and

indicated in figure 5 of the Fairfax Difficult Run

Watershed Management Plan Chapter 2 Watershed

Condtion report.

.

Figure 2 - Section 1 – 3’-4’' eroded bank

Figure 4 – Sinuosity Example

Figure 3 - Stream Condition Types

Figure 5– Difficult Run Channel Evolution Model Map

Stream Restoration Grant Proposal Wolftrap Creek – Difficult Run

Vienna VA

Page 6 of 13

TP (Total Phosphorus)

In reviewing the Difficult Run watershed management plan, as produced by Fairfax County,

several items reference the condition of the streams in the Wolftrap Creek portion of the watershed. From

chapter 2 of the report:

“Table 2.17 shows results of the hydrologic and water quality modeling, normalized by

area, so that the sub watersheds and be compared directly. There is a correlation between the

amount of development and the hydrologic results. Old courthouse Spring Branch has the highest

level of imperviousness and the highest runoff volume. Snakeden branch, Wolftrap Creek,

Colvin Run and Piney Branch also show high runoff volume and high levels of imperviousness.

The same five sub watersheds also have the highest peak flows.

Old Courthouse Spring Branch also shows up with the highest levels of TSS, TN and TP

from runoff. Wolftrap Creek, Colvin Run and Snakenden branch also have high levels of these

pollutants.”

As seen above in the table and quote the Phosphorus load in the Wolftrap Creek watershed is

considered very high. This very high rating for phosphorus further supports the need for stream

mitigation.

A map of the drainage areas is included in Appendix G.

Figure 6 – Difficult Run Sub Watershed Modeling Results

Stream Restoration Grant Proposal Wolftrap Creek – Difficult Run

Vienna VA

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The streams condition assessment indicates a significant need for restoration and stabilization. In

conjunction with the watershed’s plan finding that the Wolftrap Creek is inundated with high levels of

total phosphorus and the significant drainage area to these stream sections this project represents a prime

opportunity to achieve the Total Phosphorus reduction goal of the SLAF grant.

Stream Restoration Description

The goal of stream restoration is to return the stream to a stable state in which it; neither

significantly erodes or fills with sediment, is connected to its floodplain and has an improved habitat

condition. In so doing a connection to the floodplain is created, reducing total phosphorus discharge, as

well as preventing further erosion and bound total phosphorus discharge to the stream.

For incised urban channels, such as this one, there are several options available depending on the

severity of the section and the extent of adjacent land. The most extensive restoration portions may move

the stream itself, creating a new channel on a new alignment at the original floodplain elevation. Other

sections could involve adjusting the cross-section, reducing bank slopes, or creating a new floodplain

bench within an over-widened channel. For portions with restricted availability of adjacent land where

there is no room to increase meander width, the restoration design will use grade controls to flatten the

slope of the stream and dissipate stream energy. In the small sections where it is infeasible to recreate a

natural channel less extensive restoration approaches will be undertaken. Such measures include armoring

stream banks with rock or bioengineering materials to prevent further erosion and grading to lay back

over-steepened banks to create a more stable cross-section.

Maintenance Provisions for the long-term maintenance responsibility of the restored stream, including an

inspection and maintenance schedule, will be included in the project. Project documents will indicate the

specific maintenance requirements for the project as well as the duration and ongoing requirements and

responsibilities.

The project falls within public land owned by the Town.

Stream Restoration Grant Proposal Wolftrap Creek – Difficult Run

Vienna VA

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D: Grant Application Summary I. POLLUTION REDUCTION

“Points will be based on the calculated reduction of total phosphorous (TP) as a result of

the proposed project. The established methodology for calculating the TP reduction is

outlined in Attachment A.”

Approximately 1,020 linear feet of restored Stream:

At 0.068 lbs/ft = 69.36 lbs of removed Phosphorus

The project proposes a total of 1,020 linear feet of stream restoration with a

total of 69.36 lbs of removed Phosphorus.

II. COST EFFECTIVENESS “Points will be based on the projected cost of the project divided by the calculated

amount of TP reduction.”

Project Cost as included on the Grant Application = $890,000

Total Phosphorus Removed = 69.36 lbs

Cost Effectiveness Ratio = $12,471/lb

III. IMPAIRED WATER BODIES “Points will be based on the location and impact of the proposed project in relation to

priority water bodies in the state. . Note: These categories (a – b) are additive.

a. Project is directly related to the requirements of the Chesapeake Bay TMDL

60 pts.

b. Project is directly related to requirements of a local impaired stream TMDL

40 pts.

or

Project is directly related to a local impaired stream without a TMDL 20 pts.”

The project is not directly in a TDML plan, the project does however flow to

Difficult Run, which has some TDMLs, and then flows onto the Potomac and the

Chesapeake Bay both of which have TDMLs.

IV. FISCAL STRESS “50 of the points for county and city applicants will be based on the latest available

Commission on Local Government composite fiscal stress index. Town applicants will be

assigned the points of the surrounding county. Any applicant with a project serving more

than one jurisdiction (such as public service authorities or towns located in two counties)

will be assigned a weighted average from the component scores. An additional 25 points

will be awarded to applicants that have established a dedicated local funding/revenue

mechanism for stormwater capital projects “

The Town of Vienna has a dedicated local funding/revenue mechanism. The

Stormwater Tax is collected via Fairfax County and portions thereof are then passed onto

Vienna for use in implementing The Town of Vienna’s responsibilities.

Stream Restoration Grant Proposal Wolftrap Creek – Difficult Run

Vienna VA

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V. READINESS TO PROCEED “Because it is important that grant recipients proceed quickly with their proposed

projects, applicants that can proceed immediately with their proposed projects, or

demonstrate an advanced state of readiness, will be given the highest points under this

category.

Design has been submitted, reviewed, and approved 40 pts.

Design submitted / under review 35 pts.

Reasonable assurance design will be completed / submitted within 4 months 30 pts.

Project identified in current year Capital Improvement Plan or annual budget 20 pts.

Project included in Stormwater or Watershed Management Plan 10 pts.

Additional 10 points will be awarded if land necessary for the project has already been

acquired. “

The proposed project is in the beginning stages of coordination. Fairfax County has

committed to providing the local matching funds for this project (see letter of

commitment from Fairfax County in Appendix C. The project will be administered by the

Town. Upon notice of award of the grant, the Town will immediately acquire a design

engineer and begin the project. It can be expected that an engineer could be under

contract within three months of the notice a grant award.

No acquisition of property is required for this project. The land for the project is already

owned by the Town of Vienna.

VI. PHASE II (SMALL) MS4 “Applicants that are regulated under the General Permit for the Discharge of

Stormwater from Small Municipal Separate Storm Sewer Systems will receive 25 points.”

The Town of Vienna is regulated under a General Permit for the Discharge of

Stormwater from Small Municipal Separate Storm Sewer systems.

E: Closing In closing the Town of Vienna appreciates the opportunity to apply for grant match funds for a

critical and sorely needed Stormwater management project that will benefit the State, Fairfax County, the

Chesapeake Bay and Town while meeting our MS4 responsibilities.

Stream Restoration Grant Proposal Wolftrap Creek – Difficult Run

Vienna VA

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Appendix A – Additional Site Photographs

Stream Restoration Grant Proposal Wolftrap Creek – Difficult Run

Vienna VA

Page 11 of 13

Appendix B - Letter from Fairfax County

Stream Restoration Grant Proposal Wolftrap Creek – Difficult Run

Vienna VA

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Appendix C – Project Location Map

Stream Restoration Grant Proposal Wolftrap Creek – Difficult Run

Vienna VA

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Appendix D – Drainage Area Map

Map Source: http://www.fairfaxcounty.gov/dpwes/images/stormwater/wolftrap_map.jpg

*Edited to reflect new project

ADDENDUM #1 TO RFP 15-03.pdfNAME AND ADDRESS OF FIRM:

SLAF ApplicationNarrative - Final