Oak Creek Basin Trunk Sewer and Sub-Basin Sewers Preliminary Design Report

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Cover Page  (51 K)

Table of Contents  (44 K)

Executive Summary  (81 K)

1. Introduction

2. Findings and Evaluations of Investigations in the Project Area

3. Summary of Trunk Sewer Evaluation and Alignment Studies

4. Improvement Plan for 5,950 Acres (1,500 Tier III Acres)

5. Improvement Plan for 4,450 Acres (Existing and Tier I Areas)

6. Project Costs for Selected Improvements

7. Additional Study of Sewer Alternative along W. Mathis Street (Segment E-2)

8. Conclusions and Recommendations

1. Introduction  (1.25 M)

1.1. Scope of Study

1.2. Background

1.3. Previous Studies

• 1.3.1. Lincoln Wastewater Facilities Plan Update
• 1.3.2. Airpark West Subarea Plan
• 1.3.3. Northwest Tier Study

1.4. Other Documents

1.5. Study Area

1.6. Stakeholders

2. Findings and Evaluation of Investigations in the Project Area  (532 K)

2.1. Geotechnical Investigations

2.2. Concrete Rubble Pit

2.3. Surveying

2.4. Condition Assessment of Existing Wastewater Facilities

2.5. Existing Utilities

• 2.5.1. Alltel
• 2.5.2. Aquila
• 2.5.3. Lincoln Electric System
• 2.5.4. Lincoln Water System
• 2.5.5. Watershed Management
• 2.5.6. Magellan Pipeline Company
• 2.5.7. Sprint
• 2.5.8. Lincoln Airport Authority Utilities

2.6. Environmental

• 2.6.1. Wetlands
• 2.6.2. Hazardous Substances

2.7. Pavement and Traffic Impacts

2.8. Proposed Roadway Improvements

2.9. Proposed Natural Resources District Improvements

2.10. Public Relations

2.11. Impacts and Disruptions to Existing Businesses

2.12. Easements and Land Acquisition

2.13. Permits and Approvals

3. Summary of Alignment Studies and Trunk Sewer Evaluation  (1.06 M)

3.1 Trunk Sewer Evaluation

3.2 Summary of Alignment Studies

3.2 Order of Magnitude OPPC

4. Improvement Plan for 5,590 Acres (1,500 Tier III Acres)  (1.98 M)

4.1. Applicable Standards and Guidelines

4.2. Sewer Services Areas (Development Areas)

4.3. Design Flows and Sewer Modeling (Existing, Tier I, Future)

4.4. Sewer Replacement Evaluation

4.5. Siphon Design

4.6. Connections to Existing and Future Sewers

4.7. Pipe Design

4.8. Manholes

4.9. Construction Techniques

4.10. Special Construction

4.11. Abandoning of Existing Sewers

4.12. Project Approval Requirements

5. Improvement Plan for 4,450 Acres (Existing and Tier I Areas)  (83 K)

5.1. Applicable Standards and Guidelines

5.2. Sewer Services Areas (Development Areas)

5.3. Design Flows and Sewer Modeling (Existing, Tier I, Future)

5.4. Sewer Replacement Evaluation

5.5. Siphon Design

5.6. Connections to Existing and Future Sewers

5.7. Pipe Design

5.8. Manholes

5.9. Construction Techniques

5.10. Special Construction

5.11. Abandoning of Existing Sewers

5.12. Project Approval Requirements

6. Project Costs for Selected Improvement  (44 K)

6.1. Basis of Project Costs

6.2. Construction and Engineering Costs

6.3. Easement Acquisition Costs

6.4. Total Project Costs

7. Additional Study of Sewer Alternative Along West Mathis Street  (1.95 M)

7.1. Utility Conflicts

7.2. Modeling of Existing Trunk Sewer from MH 68 to the Oak Creek Siphon

7.3. Proposed Improvements of the Existing Trunk Sewer

7.4. Project Costs

7.5. Phased Development Plan Summary

7.6. Present Value Cost

7.7. Comparison to Recommended Development Plan in Study

7.8. Phased Development of the Preliminary Design Study

8. Conclusions and Recommendations  (55 K)

8.1. Conclusions

8.2. Summary of Additional Study in Appendix G

8.3. Summary of Additional Study in Appendix H

8.4. Project Costs

8.5. Recommended Phased Development Plan

8.6. Phase 1 Project

8.7. 1,500 Acres of Tier III Development

List of Tables

ES-1 Oak Creek Basin Areas

ES-2 Phased Const. of the Proposed Collection System Improvements (5,950 ac)

ES-3 Oak Creek Basin Areas

ES-4 Phased Const. of the Proposed Collection System Improvements (4,450 ac)

ES-5 Opinion of Probable Project Costs (5,950 acres of Development in Basin)

ES-6 Opinion of Probable Project Costs (4,450 acres of Development in Basin)

ES-7 Opinion of Probable Project Costs (5,950 acres of Development in Basin)

ES-8 Opinion of Probable Project Costs (4,450 acres of Development in Basin)

ES-9 Phased Const. of the Proposed Collection System Improvements

2-1 Utility Contact Information

2-2 Permit Information and Contact List

3-1 Hydraulic Model Inputs for Existing Oak Creek Basin

3-2 Facility Plan Update Identified Trunk Sewer Improvements

3-3 Additional Service Area Capacity at Manhole 68

3-4 Summary of Existing Capacity in the Oak Creek Collection System

4-1 Oak Creek Basin Areas

4-2 City of Lincoln Sewer Design Flow Parameters

4-3 Hydraulic Model Inputs for Existing Oak Creek Basin

4-4 Hydraulic Model Inputs for Proposed Future Flows

4-5 Phased Construction of the Proposed Collection System Improvements

4-6 Individual Siphon Design for Each Flow Condition

4-7 Composite Siphon Design for All Flow Conditions

5-1 Oak Creek Basin Areas

5-2 City of Lincoln Sewer Design Flow Parameters

5-3 Hydraulic Model Inputs for Existing Oak Creek Basin

5-4 Hydraulic Model Inputs for Proposed System Flows

5-5 Phased Construction of the Proposed Collection System Improvements

6-1 Opinion of Probable Project Costs (5,950 acres of Development in Basin)

6-2 Opinion of Probable Project Costs (4,450 acres of Development in Basin)

7-1 Hydraulic Conveyance Limitations in the Existing Segment E-2

7-2 Opinion of Probable Project Costs

7-3 Phased Construction of the Alternative Development Plan for Segment E-2

7-4 Present Value Costs

7-5 Phased Development Costs for the Preliminary Design Study

8-1 Opinion of Probable Project Costs (5,950 acres of Development in Basin)

8-2 Opinion of Probable Project Costs (4,450 acres of Development in Basin)

8-3 Phased Construction of the Proposed Collection System Improvements

List of Figures

1-1 Basin Area Map

1-2 Airport West Subarea Plan

1-3 Airpark West Master Plan

2-1 Critical Locations, Excavations, Boring Locations, Other Investigation Information (Utilities)

3-1 Existing Oak Creek Trunk Sewer (MH 68 to Theresa Street WWTF)

3-2 Trunk Sewer – MH 68 to Theresa Street WWTF (Tier I Flows)

3-3 Trunk Sewer – MH 68 to Theresa Street WWTF (Tier I + Future 1,500 Acres)

4-1 Existing Collection System

4-2 Existing Sewer Capacities

4-3 Proposed Sewer Location Map

4-4 Proposed East Basin Sewer to Manhole 68 (Tier I + Future 1,500 Acres)

4-5 Proposed West Basin Sewer to Manhole 68 (Tier I + Future 1,500 Acres)

4-6 Proposed Oak Creek Siphon (Tier I + Future 1,500 Acres)

4-7 Segment 6c and 6d – Existing 15" Sewer (Tier I Flows)

4-8 Segment 6c and 6d – Proposed 18" Sewer (Tier I Flows)

4-9 Oak Creek Siphon Design

7-1 Additional Study Alternatives A & B

7-2 Additional Study Alternative A

7-3 Existing Sewer from Manhole AA6-68 to Manhole

7-4 Phase 1 Improvements from Manhole AA6-68 to Manhole

7-5 Phase 2 Improvements from Manhole AA6-68 to Manhole

7-6 Phase 3 Improvements from Manhole AA6-68 to Manhole

Appendices

A. Preliminary Plan and Profile Drawings (200' scale)  (4.33 M)

B. Opinion of Probable Project Cost  (81 K)

C. Alignment Studies  (7.01 M)

D. Preliminary Geotechnical Report  (3.04 M)

E. SWMM Model Input Nodes and Segments (Existing and Proposed Collection System)  (1.22 M)

F. Design Basin Growth Curves for Sewer Parallel and Replacement  (307 K)

G. Capacity Analysis of Segment E-2  (677 K)

H. Analysis of Varying Design Flows, 'n' Factors, and In-Basin Pumping to Reduce Project Costs  (108 K)