ALA WAI CANAL WATERSHED WATER QUALITY IMPROVEMENT PROJECT STEERING COMMITTEE • CITY & COUNTY OF HONOLULU • STATE OF HAWAII APRIL 1998 Management & Implementation Plan Volume I Note This is a special reprint of the original For more information, please contact: report. This reprint is provided as a guide to assist the implementation of Eugene P. Dashiell, AICP, Coordinator & Steering Committee Chairman 1314 South King Street, Suite 951; Honolulu, Hawaii 96814 projects which have been funded by Telephone & Facsimile: 808.593.8330; E-mail: [email protected] the State of Hawaii (DLNR projects – June Harrigan, Ph.D., Manager, Environmental Planning Office Department of Health, State of Hawaii RFP for Design Build Contract – 919 Ala Moana Blvd., 3rd Floor, Honolulu, Hawaii, 96814 about $500,000). This reprint does not Telephone: 586.4337 include the appendices in Volume I, Alex Ho, P.E., Environmental Engineer Department of Public Works, City and County of Honolulu nor does it include Volume II. The 650 South King St., 15th Floor, Honolulu, Hawaii, 96813 Telephone: 523.4150 original report is available in libraries, from some government offices. Over 1,000 copies of the original report were printed and distributed. Table of Contents – Volumes I & 2 Chapters (Volume I) Page 1. Steering Committee’s Vision .....................................................1 Acknowledgements ...................................................................... iv 2. Consent Decree Project’s Accomplishments.............................3 3. Most Frequently Asked Question ..............................................6 Glossary.......................................................................................... v 4. Erosion Resistant Path (1930’s) Manoa Falls Trail .................16 5. Bank Erosion, Below Manoa Falls...........................................16 1. Executive Summary................................................................3 6. Erosion Control (1977), Manoa Falls Trail...............................17 7. Kanaha Stream Bank, Gateway to Punchbowl........................19 2. Recommendations.................................................................. 7 8. Makiki Stream, Corner of So. King & Kalakaua.......................19 9. Stream Restoration in El Cerrito, CA.......................................20 3. Water Quality Problems & Proposed Solutions................. 16 10. Manoa Play-field at Manoa Recreation Center........................21 3.1. Soil Erosion in the Conservation District ................... 16 11. Kaimuki H.S. – Manoa-Palolo Canal Bank Improvement ........22 3.2. Degradation & Erosion of Streams 12. Manoa-Palolo Canal & Manoa Stream Restoration.................22 in the Urban District ..................................................... 19 13. Manoa-Palolo Canal at Waialae Ave. Bridge ..........................24 3.3. Stream Quality ..............................................................25 14. Typical Cross Sections of Stream Restoration Projects ..........24 3.4. Ala Wai Canal Sedimentation & Dredging .................. 30 15. Proposed Cross-section, Manoa-Palolo Canal........................24 3.5. Flooding ......................................................................... 33 16. Maintenance Road & Bikepath Under Bridge..........................24 3.6. Vehicle............................................................................ 35 17. Stream Highlights ....................................................................25 3.7. Litter ............................................................................... 39 18. Apoha .....................................................................................25 3.8. Human Health ................................................................ 43 19. Design Considerations for Stream Channels ..........................28 19. A. Date St. to Woodlawn Dr. Corridor............... Follows Page 29 4. Existing Water Quality Conditions...................................... 47 19. B. Pedestrian Underpass, Troutbridge ............ Follows Page 29 19. C. Pedestrian Underpass, Wildcat Creek......... Follows Page 29 5. Future Water Quality Conditions......................................... 56 19. D. Pedestrian Underpass, Wildcat Creek ........ Follows Page 29 19. E. Pedestrian Underpass, Wildcat Creek ........ Follows Page 29 6. Agency and Program Issues ............................................... 60 19. F. Lower Silver Creek ...................................... Follows Page 29 19. G. Lower Silver Creek ..................................... Follows Page 29 7. Public & Private Actions:..................................................... 67 19. H. Lower Silver Creek ..................................... Follows Page 29 20. Small Dredge in Lake Merritt, Oakland....................................30 8. A Regional Approach to Management................................ 73 21. Sediment from Water Separator..............................................32 22. Swollen Ala Wai Canal After Minor Rains ...............................33 9. Costs and Benefits of Watershed Management ................ 77 22A. 100-Year Flood Plain Ala Wai Canal.............. Follows Page 34 23. The High Number of Vehicles..................................................35 References.................................................................................... 82 24. Accumulated Sediment in Storm Drain, Kapahulu Ave ...........36 25. Road Runoff Metal Reduction Methods...................................37 Index.............................................................................................. 85 26. Population of Watershed, Business Day .................................39 27. Typical Curbside Rubbish, Kapiolani Blvd/Date St..................39 28. Storm Drain Inlet......................................................................40 Figures (Volume I) Page 29. Typical Amount of Litter in Bottom of Storm Drain ..................40 Ala Wai Canal Watershed Map............................... Follows Page vii 30. Volunteers. Waikiki Yacht Club Canal Crew............................41 Management and Implementation Plan April 1998 Ala Wai Canal Watershed Water Quality Improvement Project Page [ i ] 31. State Harbor MOG Vessel ...................................................... 31 6. Beautification of Makiki Stream from King St. Along 32. Debris-Catching Boom in Lake Merritt, Oakland..................... 42 7. Kalakaua Avenue. 8. Kanaha Stream Restoration and Landscaping 32A. Debris Booms Locations (Proposed)..............Follows Page 42 9. Pukele Stream Lo’i Restoration and Trail 33. Fishers Taking Large Numbers of Tiliapia .............................. 44 10. Waiomao Stream Restoration, Trail and Community Garden 34. Tilapia Capture for Contaminant Testing – 1997 .................... 44 11. Upper Palolo Valley and Ka’au Crater Trail and Stream Restoration 35. Leptospirosis Warning............................................................. 45 12. Erosion Control in the Urban District, Especially Along Stream Banks 36. 1920 Air photo – Pre-Ala Wai Canal ....................................... 47 13. Greenbelts and Vegetative Buffers 14. Dredge Manoa-Palolo Canal Between the Ala Wai Canal & Date St. to Serve 37. Decrease in Permeability ........................................................ 48 as a Sediment Catchment Basin 38. Birds and Other Animals ......................................................... 50 15. Inject Seawater Into the Ala Wai Canal to Clarify the Water, Reduce Odor...... 39. Abandoned Car Battery........................................................... 50 16. Reduce Cans, Bottles, Bags, Cups, and Fast Food Debris from Entering 39. A. 1920 Map Ala Wai Canal..............................Follows Page 55 Streams and Canal 17. Reduce Neighborhood Rubbish Collection Problems 39. B. Permeable Area & Sub-watersheds .............Follows Page 55 18. Flood Damage Reduction Investigation of the Ala Wai Canal 40. Outrigger Canoe Under Kapahulu Ave. Bridge ....................... 56 19. Stop Illegal Construction, Filling in Streams and Reduce Rubbish Dumping .... 41. Retaining Wall, Pukele (Palolo) Stream .................................. 63 20. Dredge Ala Wai Canal between Kapahulu Av. & the Ala Wai Boat Harbor 42. Palolo Flood Control Project – Clean-up................................. 68 21. Reduce Erosion and Improve Vegetative Cover in the Conservation District 43. Palolo Pride Festival ............................................................... 68 22. Centralize All Watershed Water Quality Implementation within DLNR, Especially Streams 44. Waiomao Stream, April 1997, Large Stump............................ 69 23. Prepare a Master Plan for Watershed Management Including Project Designs, 45. Pukele Stream Channel .......................................................... 68 plans, and Specifications for Construction and an Environmental Impact 46. Waiomao Stream, October 1997, Large Stump Moved .......... 70 Statement 47. Manoa Stream – Failed Attempt at Erosion Control................ 71 Status of Legislation (as of April 15, 1998) SB 2505 – Omnibus Ala Wai Canal Watershed Legislation SB 2506 – Plastics Recycling and Advance Deposit Tables (Volume I) SB 3110 – Capital Improvements Funding 1. Evaluation of Aquatic Habitat in Ala Wai HB 3385 – Omnibus Ala Wai Canal Watershed Legislation SCR 140 – Concurrent Res. Adopting Management and Implementation Plan Canal Watershed Streams.....................................................