New Meadows Lake Tidal Restoration Feasibility Study

November 15, 2005 Steering Committee Meeting

Sponsored by: Sponsored by: Sponsored by: Sponsored by: With funding provided by:With funding provided by:With funding provided by:With funding provided by:

Study Goal & ObjectivesStudy Goal & ObjectivesTo develop and evaluate the feasibility of technical To develop and evaluate the feasibility of technical alternatives for improving water quality and enhancing alternatives for improving water quality and enhancing ecological resources in New Meadows Lake through ecological resources in New Meadows Lake through increased tidal exchange. increased tidal exchange.

Public InvolvementPublic Involvement • A key component of the study process and any ultimate A key component of the study process and any ultimate

decision-making process.decision-making process.• There will be three public forums during the study.There will be three public forums during the study.

Study ProgressStudy ProgressStudy ProgressStudy Progress

1.1. Temperature and Stage DataTemperature and Stage Data2.2. Bathymetry DataBathymetry Data

1.1. BathymetryBathymetry2.2. Stage-Volume RelationStage-Volume Relation

3.3. Preliminary Model DevelopmentPreliminary Model Development1.1. CalibrationCalibration2.2. Conceptual AlternativesConceptual Alternatives

4.4. Discussion of Conceptual AlternativesDiscussion of Conceptual Alternatives

Temperature and Stage DataTemperature and Stage DataTemperature and Stage DataTemperature and Stage Data– Temperature/Pressure Transducers Installed

July 29, 2005– Temperature/Pressure Transducers Retrieved

October 14, 2005

Stage DataStage DataStage DataStage Data– Water Surface Elevations (Stage): New Meadows

River (blue) and New Meadows Lake (red)

Bathymetry DataBathymetry Data

• Complete Bathymetry Mapping of Upper and Lower Lake

• Data Corrected for Changes in Tidal Stage

• Data in Maine West 1983 Coordinate Plane

Stage-Volume RelationStage-Volume Relation

Preliminary Model DevelopmentPreliminary Model Development

• HEC-RAS Model Development – Geometry Data From Bathymetry and Existing Information– Tidal Stage Data for Input

2400 1200 2400 1200 2400 1200 2400 1200 2400 1200 2400 1200 240003Oct2005 04Oct2005 05Oct2005 06Oct2005 07Oct2005 08Oct2005

96.0

96.2

96.4

96.6

96.8

97.0

Time

STA

GE

(fe

et)

STA

GE

(F

EE

T)

Alternative 1: Deeper CulvertAlternative 1: Deeper Culvert

• Existing Culvert Alignment and Width with Invert Set 2.4-ft Below Current Invert

• Lower Typical Lake Level• Tidal Stage Variation Does

Note Change

Alternative 2: Deeper/Wider CulvertAlternative 2: Deeper/Wider Culvert

• Existing Culvert Alignment and Double-Width (24-ft) and Invert Set 4.4-ft Below Current Invert

• Lower Typical Lake Level• Tidal Stage Variation Does

Note Change

Alternative 4: Bridge Replacing Alternative 4: Bridge Replacing CulvertCulvert

• Bridge Through Embankment• Width of 50-ft• Invert Set Below MLW

Alternative 4: Bridge Replacing Alternative 4: Bridge Replacing CulvertCulvert

• Substantial Tidal Stage Variation

2400 1200 2400 1200 2400 1200 2400 1200 2400 1200 2400 1200 240003Oct2005 04Oct2005 05Oct2005 06Oct2005 07Oct2005 08Oct2005

88

90

92

94

96

98

100

Time

STA

GE

(F

EE

T)

Thank youThank you

Questions? Comments?Questions? Comments?