South Side Red River Bridge Corridor StudySouth Side Red River Bridge Corridor Study

Phase III

Preliminary Geotechnical Study

Phase IV

New Alignment Alternatives Evaluation

Study Review Committee (SRC) MembersStudy Review Committee (SRC) Members

Jack Cousins - Clay County Engineer

Tim Magnusson - Clay County Planner

Brian Gibson - Transportation Analyst, F-M Metro COG

Richard Lane - Traffic Engineer, Fargo

Cindy Gray - Senior Planner, Fargo

Bob Bright - Executive Director, F-M Metro COG

Mark Bittner - City Engineer, Fargo

Project TimelineProject TimelineSpring 1998 – Initiated Study

July 1998 – Public Meeting #1

September 1998 – Public Meeting #2

December 1998 – Joint Planning Commission Meeting

January 1999 – Neighborhood Rebuttal

March 1999 – Phase I Final Report

2000 – Initiated Phase II Supplemental Study and Neighborhood Response

2000 – Completed Land Use Analysis for Study Area

May 2001 – Neighborhood Response

May 2001 – Phase II Report

June 2001 – Joint Planning Commission Meeting

2002 - Initiated Phase III Geotechnical Study

January 2003 - Phase III Geotechnical Study Report

February 2003 - Initiated Phase IV Study Report

March 2003 - Phase IV Study Report

Overall Study Goals & ObjectivesOverall Study Goals & Objectives

Preserve a corridor between 52nd Avenue S. and 88th Avenue S. that will be needed 15-20 years from now.

Decision will allow the City of Fargo, Clay County, Cass County, and the City of Moorhead to do long range planning for one type of corridor or the other.

Decision will allow the affected residents to do their own long range planning.

Phase I Study ResultsPhase I Study Results Technical evaluations of 11 alignment

alternatives.

70th Avenue S. and 76th Avenue S. were both feasible and met study objectives.

The Forest River Neighborhood Preservation Committee prepared a detailed review of the Phase I Report.

This feedback resulted in a response document and the development of the Phase II Supplemental Report.

Phase II Study ResultsPhase II Study Results Added a new alternative: The combined

70th/76th Avenue S. alternative.

Sub-Alternative A for the 76th Avenue S. Alternative was selected to minimize both the impacts of the arterial upon the neighborhood and the impacts of the neighborhood streets upon the arterial.

All three alignment alternatives feasible.

Final Three AlternativesFinal Three Alternatives

Criteria

System Continuity and Route Direction

Interchange Spacing

Land Use Planning

Traffic Operations

Mainline Length

Length of Supporting Roads

Residential Acquisitions

Neighborhood Severance

Homes Adjacent to New Roadways

Farmland Severance

Cost

70th Avenue S. Alternative

No direct connections

1.5 miles

Introduces .5 mile arterial spacing

Optimal

6.2 miles

0 feet

None

None

8

Greater

$22.2 million

76th/70th Avenue S. Alternative

Direct connection to the west

2 miles

Introduces .5 mile arterial spacing

Indirect travel route

6.4 miles

0 feet

None

None

8

Greater

$22.7 million

76th Avenue S. Alternative A

Direct connections to the west and east

2 miles

Consistent with 1 mile arterial planning

Add’l full accesses

6.2 miles

3,600 feet

10

Minimized

14

Least

$23.5 million

Phase II Technical Comparison of Final Three Alternatives Phase II Technical Comparison of Final Three Alternatives

Phase III Study Goals & ObjectivesPhase III Study Goals & Objectives Determine the geotechnical feasibility of

crossing the Red River at 70th and 76th Avenues.

Refine alignment alternatives and bridge lengths based upon study findings.

Update Cost Estimates based upon study findings.

Soil Stability AnalysisSoil Stability Analysis Soil borings provided a cross-section of soils

near the crossing locations of 70th and 76th Avenues

Analysis resulted in top of riverbank setback requirements at 70th and 76th crossing locations and approach embankments.

Additionally, river bed rip-rap is required at the crossing location and adjacent to the approach embankments of the 76th Avenue Alternative.

Soil Stability Analysis ResultsSoil Stability Analysis Results 70th Avenue Setbacks:

– 30 feet from elev. 905 on west riverbank– 0 feet on east riverbank

76th Avenue Setbacks:– 120 feet from elev. 905 on west riverbank– 140 feet from elev. 902 on east riverbank– 60 feet from elev. 905 on west approach embankment

(from oxbow to the north)– 220 feet from elev. 902 on east approach embankment

(from oxbow to the north) Additional geotechnical analysis recommended at

final bridge location

Geotechnical ConsiderationsGeotechnical Considerations

Backwater EffectsBackwater Effects A preliminary backwater (flooding) analysis

was conducted at each river crossing location using a draft HEC-RAS (Hydraulic Engineering Center River Analysis System) model developed by Houston Engineering.

With the recommended setbacks, neither crossing alternative will affect the hydraulic capacity of the river channel.

Bridge AdjustmentsBridge Adjustments All bridges aligned to cross on a tangent

70th Avenue: 1,170-foot bridge length

76th Avenue: 1,200-foot bridge length, 2 300’x10’x10’ Box Culverts to cross County Ditch 32

Alignment Adjustments & ImpactsAlignment Adjustments & Impacts No change under the 70th Avenue

Alternative.

No change under the 76th/70th Avenue Alternative.

Significant changes under the 76th Avenue Alternative due to abutment and approach embankment setbacks.

Phase III Conclusions & RecommendationsPhase III Conclusions & Recommendations Applying the required setbacks and rip-rap,

both the 70th and 76th Avenue crossings are technically feasible.

Hydraulic capacity of the Red River channel can be maintained with the proposed bridge abutment setbacks and bridge profile.

An additional bridge crossing location south of the 76th Avenue Alternative should be considered in a fourth phase of the study.

The Phase IV study will identify this new alternative(s) to be evaluated alongside the current alternatives, for the purpose of selecting a preferred alternative.

Phase IV Study Goals & ObjectivesPhase IV Study Goals & Objectives

Identify new alternatives to ease impacts and reduce construction costs.

Evaluate new alternatives against the three previous alternatives.

Update Cost Estimates based upon study findings.

Select a preferred alignment alternative.

70th Avenue Alternative70th Avenue Alternative

76th/70th Avenue Alternative76th/70th Avenue Alternative

76th Avenue Alternative76th Avenue Alternative

New South 76th Avenue Alternative (Dismissed)New South 76th Avenue Alternative (Dismissed)

New “Jogged” South 76th Avenue AlternativeNew “Jogged” South 76th Avenue Alternative

New “Jogged” 76th/70th Avenue AlternativeNew “Jogged” 76th/70th Avenue Alternative

FEMA Flood Buyout PropertiesFEMA Flood Buyout Properties The 76th Avenue, “Jogged” South 76th

Avenue and “Jogged” 76th/70th Avenue alternatives require the use of lots purchased with FEMA Hazard Mitigation Grant Program (HMGP) funds.

If the preferred alternative uses any HMGP buyout lots, FEMA would want to investigate the environmental consequences of the alignment versus other alignments.

Approval of use would be subject to environmental review. Reimbursement of funds is unlikely.

Comparative Cost EstimateComparative Cost Estimate

Phase IV Conclusions & RecommendationsPhase IV Conclusions & Recommendations All five of the bridge location and corridor

alignment alternatives are technically feasible. With the exception of the original 76th Avenue

Alternative, all other alternatives have similar costs.

The “jogged” alignments are less desirable for an arterial roadway serving east-west trips.

Each alternative results in different pros and cons as they relate to residential impacts, route continuity, traffic operations and cost.

Elected officials should weigh these factors in the selection of a preferred alternative.

Next StepsNext Steps Who should complete this??