Strategic Monitoring and Resilience Training in the Ala Wai Watershed, Oʻahu: Seasonal and Episodic Variability

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dc.contributor.advisorGlazer, Brian
dc.contributor.authorChen, Solomon
dc.contributor.departmentOceanography
dc.contributor.departmentGlobal Environmental Science
dc.date.accessioned2022-10-07T19:08:02Z
dc.date.available2022-10-07T19:08:02Z
dc.date.issued2020
dc.description.courseOCN 499 - Undergraduate Thesis
dc.identifier.urihttps://hdl.handle.net/10125/102403
dc.publisher.placeHonolulu
dc.subjectwatershed
dc.subjectwater quality
dc.subjectala wai canal
dc.subjectdata
dc.subjectsensor
dc.titleStrategic Monitoring and Resilience Training in the Ala Wai Watershed, Oʻahu: Seasonal and Episodic Variability
dc.typeThesis
dcterms.abstractThe Ala Wai Canal is an artificial estuary connecting three major streams (Makiki, Palolo, Mānoa) and numerous city drainages to the ocean in Honolulu, Hawai’i. The Ala Wai Canal is where the terrestrial influence from the watershed meets oceanic forcing (e.g. tides, salinity). However, extensive urbanization has led to severe eutrophication in the Ala Wai Canal. Limited previous watershed data inhibits restoration and resilience efforts in Ala Wai Canal and the watershed. In order to understand the biogeochemical interactions and anthropogenic inputs within the watershed, this study aims to construct high-resolution spatial and temporal characterizations of current physical and chemical parameters. Monthly water quality surveys and sampling were conducted at 12 sites along three major streams in the watershed; bathymetry mapping, sensor profiling, and discrete water sampling were conducted in the canal and in the nearshore water. A high-resolution bathymetry survey in the canal was conducted at the beginning of the study period. Sensor data included temperature, salinity, dissolved oxygen, chlorophyll, and turbidity, while discrete samples were analyzed for dissolved inorganic nutrients and dissolved inorganic carbon. Vertical stratification and horizontal gradients in the Ala Wai Canal were strongly affected by runoff from episodic rain events, tidal mixing, and canal bathymetry. Bathymetry mapping and sensor surveys indicate that lateral mixing is primarily inhibited by sediment shoals, while vertical mixing was largely affected by salinity gradient. Increased runoff facilitates the vertical mixing downstream to major freshwater inputs. Data also shows that the restricted end of the canal was largely anoxic in the bottom water due to limited ventilation and enhanced organic matter respiration. Quantification of physical/chemical parameters can assist in understanding urbanization and ecological effect, which is especially important for future planning, legislation, engineering, and resilience decisions.
dcterms.extent72 pages
dcterms.languageEnglish
dcterms.publisherUniversity of Hawaiʻi at Mānoa
dcterms.rightsAll UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
dcterms.rightsHolderChen, Solomon
dcterms.typePDF

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