(3) An area 3.3 square miles is drained by the Waialae-Nui and Kapakahi Streams. Kapakahi Stream extends from the foot of the Koolau Mountains to Maunalua Bay. The Waialae-Nui Stream begins at the Koolaus and enters the Kapakahi Stream in the Waialae golf course on the downstream side of Kalanianaole Highway.

(4) An area of 0.2 square mile drains by overland flow into interior drainage structures along Luawai Street. The flow is conveyed to Waialae major drain which drains into the ocean.

(5) An area of 0.5 square mile is served by a system of interior drainage structures and a pumping station to convey water to various outlet structures. Approximately 0.1 square mile drains by gravity into Kapakahi Stream. The Waialae major drain collects water from approximately 0.1 square mile, and 0.3 square mile is drained by interior drainage structures.

Except for the steep slopes and forest reserve, the entire drainage basin is almost fully developed into residential and commercial use. The portion of Kaimuki which drains into the low-lying Waialae-Kahala area is a densely developed residential area. The only exceptions are the Army installation at Fort Ruger on the foot of Diamond Head, a cemetery, and three secondary schools. Maunalani Heights and Wilhelmina Rise are a combination of old and new homes, fully developed residential, apartment and commercial areas. Below Kalanianaole Highway is the low-lying Waialae-Kahala subdivision, a highly developed residential area with its own shopping center and schools. More than 1,000 homes, some costing in excess of $100,000, are in the area. The Waialae golf course, through which Kapakahi Stream flows to the ocean, is adjacent to the Waialae-Kahala subdivision on the east.

Flooding of the Waialae-Kahala shopping center and residential developments in the subdivisions is the major problem. The existing Waialae major drain and the Kilauea major drain are inadequate to carry flood flows originating in higher elevations.

The contemplated plan of improvement would provide protection from floods with a recurrence interval of 100 years and a range in discharges from 2,000 to 10,000 cubic feet per second with 10,000 cubic feet per second being the design flow for lower Kapakahi Stream.

The plan provides for a system of diversion channels, levees, and stream improvements. The estimated first cost of the contemplated improvement is $1 million, of which $880,000 is Federal.

A detailed project study is currently underway.

WAILUPE STREAM

(See p. 62 for survey map.)

The Wailupe Stream drainage basin lies on the leeward slopes of the Koolau Mountains between the east side of Wiliwilinui Ridge and the west side of Hawaiiloa Ridge. The basin is approximately 3 miles long and 1 mile wide, and drains an area of 3 square miles from elevation 2,600 feet to sea level. The lower one-fourth of the drainage basin contains the Aina Haina residential subdivision which is bisected by Wailupe Stream.

The contemplated plan of improvement consists of enlarging and lining the existing channel with concrete for a distance of approximately 6,100 feet with a proposed channel cross-section of a 30-foot bottom width, a 9-foot depth including a 2-foot freeboard, and a side slope of 1 on 1. The limits of improvement would be from the mouth of Wailupe Stream to the vicinity of Ani Street Bridge. The three existing bridges over the stream are of adequate capacity to pass the design flow with the proposed channel conditions.

The plan of improvement provides for enlarging and lining the existing channel for a distance of approximately 6,100 feet. The estimated first cost of the proposed improvement is $1.2 million of which $1 million is Federal.

A fully funded detailed project study is being conducted under section 205 authority. The completion of the study is scheduled for 1969.

KULIOUOU STREAM FLOOD CONTROL PROJECT

(See p. 63 for survey map.)

Kuliouou Stream is the principal stream draining Kuliouou Valley, an area of 1.6 square miles on the leeward slopes of the Koolau Mountains approximately 11 miles east of Honolulu. The lower 0.77 square mile of the valley is built up into the Kuliouou residential subdivision which includes a flood plain of about 0.11 square mile. The population of the area has increased from 800 in 1950 to 1,700 in 1963. About 42 percent of these people reside in the flood plain area. This project was authorized for construction under section 205 of the 1948 Flood Control Act. The construction plans and specification include improving the existing stream by excavation, concrete lining a major portion of the existing stream, adding supplemental walls on the banks of the existing improved trapezoidal channel, and construction of a rectangular reinforced concrete lined ditch 7 feet wide to carry interior drainage downstream of Kalanianaole Highway. Local interests are required to replace two bridges and relocate utilities.

The contract for construction of this project was awarded in August 1968. Construction has begun and is scheduled to be completed in March 1970. The contract cost is $1,595,000. This includes the cost for construction of the two bridges and relocation of waterlines which are being performed at the request of local interests and with funds contributed by them.

MAUNALUA BAY HARBOR

(See p. 64 for project drawing.)

Maunalua Bay Harbor for light-draft vessels will be located approximately 11 miles east of downtown Honolulu within the eastern half of Maunalua Bay southeast of the mouth of Kuliouou Stream. This area is in the heart of rapidly expanding residential developments serving Honolulu.

This harbor is one of eight recommended for Federal construction in the "Interim Report on Survey of the Coasts of the Hawaiian Islands Harbors for Light-Draft Vessels" and was authorized by the River and Harbor Act of 1965. Advance engineering funds totaling $32,000 have been appropriated for Maunalua Bay Harbor.

The harbor site is in a wide shallow reef of protected coast. At the site the coral formation extends seaward about 2,800 feet. The authorized plan of improvement provides for a protected harbor basin of approximately 44 acres with a berthing capacity of about 950 small craft. The basin would be enclosed by revetted moles 2,900 and 1,950 feet long. The entrance channel, 870 feet long and 200 feet wide, would extend seaward from a widened channel section of about 370,000 square feet. This channel alinement minimized the distance to deep water.

An architect-engineering firm engaged by the city and county of Honolulu has prepared a master plan for recreational use of Maunalua Bay with the harbor project as a principal feature. The Honolulu engineer district is coordinating a proposed harbor plan, which would ultimately accommodate 1,100 boats, with State and city and county officials. The draft of the design memorandum is scheduled to be completed in the winter of 1969. The estimated costs and harbor capacity are as follows:

1st cost..

Federal cost..

Non-Federal cost

Design capacity (boats).

$1,486, 000 $666, 000 $820,000 950

AIEA STREAM

(See p. 65 for survey map.)

The Aiea drainage basin of 1.9 square miles is on the southern coast of the island of Oahu approximately 7 road miles northwest of Honolulu. The basin is 3.8 miles long and averages about 0.5 mile in width. It extends from Pearl Harbor to the leeward slopes of the Koolau Range. The drainage basin is divided into two areas. Area 1 drains 0.5 square mile and area 2, 1.4 square miles and is the principal drainage of Aiea Stream.

A study under the authority of section 205 of the Flood Control Act of 1948, as amended, is underway. The contemplated plan of improvement provides for 1,700 feet of concrete channel beginning 170 feet upstream of Maunalua Road and ending 200 feet downstream of Kamehameha Highway. The planned channel varies in base width from 16 to 24 feet in the upper reach and transitions to a 45-foot width at the Kamehameha Highway Bridge. The channel design capacity is 5,000 cubic feet per second (100-year frequency).

The estimated first cost of the project is $1,760,000 of which $1 million would be Federal. WAIMALU STREAM

(See p. 66 for survey map.)

The Waimalu drainage basin is on the southern coast of the island of Oahu approximately 11 road miles northwest of Honolulu. The drainage basin is shaped like an elongated triangle with palmate stream characteristics and extends from Pearl Harbor to the Koolau Range, approximately 7 miles in length. The basin rises gently from a flat coastal plain to an elevation of 2,570 feet. The total drainage area is 8.1 square miles.

A detailed project study under the authority of section 205 of the Flood Control Act of 1948, as amended, is underway. The contemplated plan of improvement provides for 6,500 feet of channel improvement extending from Pearl Harbor to approximately 2,700 feet upstream of Moanalua Road. Existing improvements would be modified and integrated into the proposed plan. The trapezoidal channel from Pearl Harbor to Kamehameha Highway Bridge would have an 80-foot bottom width with side slopes of 22 to 1. The invert and side slopes under the Kamehameha Bridge would be paved with concrete.

The 2,900-foot reach between Kamehameha Highway and Moanalua Road would have a minimum bottom width of 100 feet. An earth levee with riprapped side slopes of 2 to 1 would be constructed only along the right bank fronting the school area. No increase in wall height along the existing 400-foot concrete lined walls or construction of a levee along the remaining right bank are contemplated as future developments of this unimproved area will provide flood protection. The existing concrete lining on the left bank of the channel would be retained and additional wall heights would be provided. The 2,700-foot reach upstream of Moanalua Road would consist of a concrete rectangular section with a minimum width of 50 feet for a 500-foot reach and a trapezoidal, concrete-lined channel with a 30-foot bottom width and 2 to 1 side slopes upstream of the rectangular channel. A minimum 2-foot freeboard would be provided along the entire improvement.

The proposed improvements would contain flows up to 17,000 cubic feet per second in the lower reaches and 14,300 cubic feet per second in the concrete channel above Moanalua Road (both discharges are for 100-year frequency floods). The first cost is estimated at $2,640,000, of which Federal cost is $1 million. The study is scheduled to be completed in 1969.

WAIANAE HARBOR

(See p. 67 for project drawing.)

The town of Waianae is on the lee of the Waianae Mountains on the west coast of the island of Oahu, approximately 30 road-miles from Honolulu. The population of the Waianae area, including adjacent Makaha, was 6,844 in 1960. The Waianae judicial district, the immediate tributary area of the proposed harbor, had a population of 16,452 in 1960, an increase of 9,428 from 1950. The population is expected to increase to 20,000 in 1980.

The present State small boat harbor for about 70 craft is immediately north of Kaneilio Point, a narrow, rocky peninsula which projects seaward about 1,000 yards in front of the town and forms the southern boundary of the waters known as Pokai Bay. Littoral drift from the north is trapped within the boat basin and frequent removal and redistribution of sand are necessary. In addition to high maintenance costs, the harbor conflicts with the recreational use of the adjacent swimming beach. For these reasons, the State of Hawaii desires to develop a small boat harbor at the site on the south side of Kaneilio Point.

This is one of eight harbors recommended for Federal construction in the interim report on the coasts of Hawaiian Islands. The eight harbors were

authorized by the River and Harbor Act of October 27, 1965. No advance engineering funds have been appropriated.

The authorized harbor, subject to model testing, would have a berthing area of 10 acres for 380 boats. The plan provides for a generally rectangular-shaped harbor basin, protected by a rubble-mound breakwater 1,350 feet long, extending in a southeasterly direction from Kaneilio Point. A second rubble-mound structure 175 feet long would be at the southeast end of the harbor basin. The general navigation channels would consist of an entrance channel, 830 feet long by 150 feet wide, dredged to a depth of 17 feet for the seaward 230 feet and with a transition to 15 feet for the remaining distance; and a main access channel 870 feet long to the berthing areas. The access channel would have a transition from a 150-foot width and 15-foot depth in its outer portion to a 100-foot width and 12-foot depth.

The estimated costs and project economics are as follows:

The Haleiwa small boat harbor is the first Federal-State small boat harbor on the island of Oahu. Prior to improvements in the harbor, light-draft vessels used the banks of the lower reaches of the Anahulu River for mooring, and pleasure boats used the launching facilities at the harbor. Boatowners experienced many difficulties under these conditions. The entrance channel frequently silted causing many vessels to run aground during storm wave activity thereby blocking the entrance channel to further navigation. Flash floods tore boats from their moorings and brought debris downriver damaging boats and creating hazards to navigation.

The project was authorized under the authority of section 107 of the River and Harbor Act of 1960. Prior to construction of the project, section 310 of the River and Harbor Act of 1965 increased the Federal limits of participation from $200,000 to $500,000. The Federal portion of the project was completed in 1966. The Federal project provides an entrance channel 610 feet long, 120 feet wide, and 12 feet deep; a revetted mole 1,200 feet long; a diversion channel for the Anahulu River 520 feet long and 80 feet wide; and a protected harbor area of about 7.4 acres. The project first cost was $490,000, of which 60.2 percent, or $295,000, was Federal cost, with the remaining $195,000 borne by the State of Hawaii.

In September 1967, the State completed the first phase of their development of Haleiwa small boat harbor at a cost of approximately $300,000. This phase provided for the dredging of a berthing area and construction of 20 catwalks to accommodate 40 boats, construction of a marginal wharf adjacent to the launching ramp, paving of the area behind the catwalks and marginal wharf, and installation of utilities services. Through incremental development, the State plans to increase the capacity of Haleiwa small boat harbor to 220 boats by 1980.

HALEIWA BEACH EROSION CONTROL PROJECT

(See p. 69 for project drawing.)

Haleiwa Beach is on the eastern arm of Waialua Bay, 31 miles from the city of Honolulu. Waialua Bay, on the north-central shore of the island of Oahu, is used for recreation by the population of the immediate area, approximately 8,000 people, as well as the residents of the entire island, 500,000 people. The eastern part of the bay contains the Haleiwa small boat harbor, the mouths of the Anahulu River and the Loko Ea Stream, and Haleiwa Beach.

Formerly, Waialua Bay had three large sandy beaches. The beaches of the Hawaiian Islands are constantly changing their composition, structure and volume, because of shifts in the volume of the littoral drift. In the 1940's, a large

beach located at the present Haleiwa Beach Park eroded away to 5,000 square feet of sand above the mean high water mark, because of such a shift in the littoral drift.

Restoration of the beach was completed by the State of Hawaii in 1965. An artificial placement of 1,600 feet of beach, from the north side of the Haleiwa Beach Park pavilion south to the Loko Ea Stream mouth, is protected by a 520-foot groin at the south end of the beach, and a 160-foot breakwater offshore opposite the park pavilion. The beach varies in width from 140 to 265 feet above the mean lower low water line. The beach was formed with 30,000 cubic yards of beach core material overlain by 60,000 cubic yards of beach sand blanket. The project was completed by the State of Hawaii in 1965 according to plans approved by the Chief of Engineers. The River and Harbor Act of October 27, 1965 authorized the project and allowed Federal participation in the amount of 60 percent of the first cost of improvements for restoration and protection of the shores of Haleiwa Beach. The project cost is $400,000, of which $240,000 is Federal cost and $160,000, non-Federal.

HEEIA-KEA HARBOR

(See p. 70 for project drawing.)

Heeia-Kea is a small community on the northeast coast of Oahu on Kaneohe Bay, approximately 3 miles from the town of Kaneohe and about 15 miles from Metropolitan Honolulu. As an interim measure, the State of Hawaii has recently expanded the existing small boat facility to now accommodate 135 craft. The town of Kaneohe had a population of 14,400 in 1960.

Variable tradewinds are predominant throughout most of the year at this site. The shoreline of the area is bordered by a fringing reef formation varying in width from 500 feet to one-half mile, with depths from 0 to 3 feet within the reef areas. The mean tidal range is 2.1 feet with a maximum range of about 4.5 feet. Littoral drift along the bay shore is negligible, and storm waves in the inner bay higher than 3 feet are infrequent.

This is one of eight harbors recommended for Federal construction in the Interim Report on the Coasts of Hawaiian Islands. The eight harbors were authorized by the River and Harbor Act of October 27, 1965. No advance engineering funds have been appropriated.

The authorized plan provides a tricompartmentalized harbor of approximately 47 acres to accommodate 1,600 boats, which is the projected boat population of the area for the year 2010. The northern compartment would be protected by a revetted mole 1,450 feet long and served by a combination entrance and access channel 570 feet long, 150 feet wide, and 12 feet deep. The large central compartment would be protected by a north mole 1,780 feet long, and a south mole 1,720 feet long, and served by an access channel 150 feet long, varying in width from 150 to 280 feet, and having a depth of 8 feet. A trapezoidal shaped access channel 8 feet deep to the existing mole and basin would also be dredged. The estimated cost and project economics are as follows:

The authorized study includes several drainage areas located within the geographic districts of Kahaluu, Kaneohe, and Kailua. The current study is concentrated on the drainage basin for the Kamooalii and Kaneohe Streams. This area suffered the worst damages in recent years. Several thousands of dollars in flood damage were sustained and two lives were lost.

The Kamooalii and Kaneohe drainage basin is on the eastern part of the island of Oahu on the windward slopes of the Koolau Mountains. It is ell shaped, having a length of about 5 miles and a width varying from 0.5 to 1.8 miles. The total area of this drainage basin is about 5 square miles.

21-793 0-69- -5