Ka`ahakini Stream Diversion Tunnel...to Kolekole Stream

A major engineering feat was needed in 1910 to build the railroad bridge across Kolekole Stream. A diversion tunnel and the resulting "waterfall" are that feat. Details were reported in a 1911 Hawaii Herald article featuring Arthur C. Alexander's presentation at a meeting of the Honolulu Social Science Association, showcasing the engineering features of the Hamakua extension of the Hilo railroad. Here's an excerpt:
  • ..."Beyond Honomu is a rather unique diversion tunnel. Two deep gulches, the Kolekole and Ka`ahakini, reach the sea almost side by side. Over the Kolekole Stream a steel bridge almost 90 feet high is being built under which almost any amount of water can pass. A tunnel about 200 feet long has been driven through the intervening ridge, thus diverting the waters of the Ka`ahkini Stream into its neighbor, the Kolekole, and enabling a solid fill to be made across the Ka`ahkini Gulch."...
Picture
Source: https://ags.hawaii.gov/survey/map-search/ then add HTS PLAT 755 where indicated
A segment of Hawaii Terretory Survey Plat Map 755 of Kaiwiki 3 Homesteads, dated January 1915, shows the narrow stretch of land separating where the Ka`ahakini and Kolekole Streams enter the ocean. The areas indicated for the diversion tunnel and the solid fill are approximate.
To view Hawaii Territory Survey Plat Map 755 of Kaiwiki 3 Homesteads, dated January 1915, click here.
A segment of Hawaii Territory Survey Plat Map 754 of the Wailea Government Remainder, dated August 1919, shows the location of the diversion tunnel. To view Plat Map 754 in its entirety, click here.

While this diversion started out as a tunnel, it collapsed at one point (date unknown), yet continues as a cut instead of a tunnel, effectively diverting the water.
Picture
https://ags.hawaii.gov/survey/map-search/ then add HTS PLAT 754 where indicated
The final reward...the railroad bridge across Kolekole Gulch...and a "waterfall".
Water from the Ka`ahakini Stream cascades into the Kolekole Stream across from one of the reinforced concrete towers of the current highway bridge. The railroad bridge was destroyed in the tsunami of April 1, 1946 and replace by the new highway bridge opened May 25, 1951.

​Photos courtesy of Susan Forbes.
For the Hakalau Kuleana, our responsibility is to care for the land, the people, and the culture. We are guided by cultural values of YESTERDAY: Engage in collective effort. Look out for each other. Honor hard work. Show respect for those who came before us. Aloha and Mālama `Aina. In 2021, Akiko Masuda added two more values to the list: Consistently show up. Whatever has to be done, jump in and do it!