Hawaii OSDS Technology Suitability Analysis

Project Wrap-Up

Alemarie Ceria

2026-05-03

Introduction

• Frame the project: Hawaii has the highest density of cesspools in the US; HAR 11-62 governs replacement options.
• Walk through the four key endpoints at a high level before diving into Methods.
• Note that the full handoff site is reachable from the slide deck through the Full methods links.

Objectives

To be filled in.

Key Endpoints

1. Download Datasets
2. Prepare Input Data
3. Build MPAT
4. Screen Techs

See full methods on the wrap-up site

Methods

• Each endpoint corresponds to a numbered notebook (00 through 03).
• The pattern is identical across all four: setup, inputs, processing steps, outputs, resources.
• Spend most time on the MPAT build and the screening pipeline. The download and prepare steps are short and mechanical.

Methods overview

Four notebooks chain in numerical order:

1. Download Datasets (notebook 00) → data/01_inputs/source/
2. Prepare Input Data (notebook 01) → data/01_inputs/prepared/
3. Build MPAT (notebook 02) → data/03_processed/mpat/
4. Screen Techs (notebook 03) → data/03_processed/tech_screening/

Each section that follows covers one endpoint with a title, inputs, processing, outputs, and resources.

Download Datasets

The notebook fetches the source layers used in the parcel suitability analysis (parcels, hydrology, soils, building footprints, regulatory boundaries, cesspool inventory) into a staged source directory.

Full methods

Download Datasets — Inputs

15 source layers in 5 categories:

• Hydrology (water table, streams, wells, rainfall)
• Soils
• Topography (DEM, slope)
• Parcels and buildings (parcels, footprints, cesspool inventory)
• Regulatory (coastline, SMA, flood zones)

Full inventory

Download Datasets — Processing

1. Import modules and helper functions
2. Specify project and raw source data directory paths
3. Specify data source links per download method type
4. Download all data or individual data layers

Download Datasets — Resources

• Notebook: 00_download_input_layers.ipynb
• Helper functions: src/download_input_layers.py
• Source directory: data/01_inputs/source/

Prepare Input Data

The notebook reprojects, mosaics, and converts source layers into a single set of analysis-ready files at a common CRS.

Full methods

Prepare Input Data — Inputs

• Source folder: data/01_inputs/source/
• See: Download Datasets — Outputs

Prepare Input Data — Outputs

• Prepared folder: data/01_inputs/prepared/
• CRS: EPSG:32604
• Rasters: rainfall, DEM, slope, watertable
• Vectors: building footprints, cesspool inventory, coastline, flood zones, parcels, SMA, soils, streams, domestic wells, municipal wells

Prepare Input Data — Processing

1. Import modules and helper functions
2. Specify configurations (target CRS)
3. Specify project and data directory paths
4. Build file paths to each source input and matching output
5. Prepare all or individual layers

Prepare Input Data — Resources

• Notebook: 01_prepare_input_layers.ipynb
• Helper functions: src/prepare_input_layers.py
• Prepared directory: data/01_inputs/prepared/

Build MPAT

The notebook joins the prepared layers into a single per-parcel attribute table for the pilot islands (Maui, Oahu, Kauai). One row per cesspool-bearing parcel, sampled at one analysis point per parcel.

Full methods

Build MPAT — Inputs

• Prepared folder: data/01_inputs/prepared/
• CRS: EPSG:32604
• Same raster and vector list as Prepare Input Data outputs.
• See: Prepare Input Data — Outputs

Build MPAT — Processing

1. Set up (configs, paths, inputs dict)
2. Load and filter cesspools (class IV, OSDS > 0, pilot islands)
3. Filter and dissolve parcels (one row per TMK)
4. Process building footprints (TMK assignment, per-parcel aggregation)
5. Define parcel analysis points (largest footprint centroid, else parcel centroid)
6. Compute spatial attributes at analysis points (SMA, flood, soils, coast, streams, wells, raster sampling)
7. Assemble MPAT (merge, derive depth_to_wt_ft and net_parcel_area_sqft)
8. Export GeoPackage and CSV

Build MPAT — Outputs

• MPAT: data/03_processed/mpat/20260428_mpat_32604.gpkg
• CSV mirror: data/03_processed/mpat/20260428_mpat.csv
• README: data/03_processed/mpat/README.md
• Parcel analysis points: data/03_processed/20260428_parcel_analysis_points.gpkg
• GitHub: data/03_processed/mpat/

Build MPAT — Resources

• Notebook: 02_built_mpat.ipynb
• Helper functions: src/build_mpat.py
• Validation: src/validate_mpat.py

Screen Techs

The notebook applies HAR 11-62 site suitability criteria to the MPAT and assigns each parcel a set of recommended cesspool replacement technologies.

Full methods

Screen Techs — Inputs

• MPAT: data/03_processed/mpat/20260428_mpat_32604.gpkg
• Configuration source: HCPT_Matrix_v6.1.xlsx (editable Excel)
• Configuration runtime files (YAML, derived via src/export_config.py):
  • config/baseline/criteria.yaml
  • config/baseline/endpoint_rules.yaml
  • config/baseline/thresholds.yaml
• Full reference: Configuration Reference (Thresholds, Criteria, Endpoint Rules tables)

Screen Techs — Processing

1. Set up (paths, output names)
2. Load MPAT and configuration
3. Feature engineering (perc_est, dist_to_nearest_well_ft)
4. Pass 1: criteria evaluation (per-parcel pass/fail per criterion)
5. Pass 1: endpoint screening (PASS or EXCLUDE per parcel × endpoint)
6. Pass 2: display filters (mark some PASS as HIDDEN)
7. Planning flags and output category (CAT_1, CAT_2, CAT_3, CAT_LAST_RESORT, CAT_SUPPLEMENT_ONLY)
8. Build per-parcel summary and export

Screen Techs — Endpoints

15 endpoints: 13 primary treatment + disposal combinations (E01–E13) plus 2 eco supplements (ES1, ES2). Examples:

• E01: Standard Septic Tank + Standard Leach Field
• E07: NSF 40 ATU + Seepage Pit
• E11: NSF 245 ATU + Subsurface Drip Irrigation
• E13: Composting or Incinerating Toilet
• ES1: Bioreactor Garden
• ES2: Constructed Wetland

Full endpoint table

Screen Techs — Outputs

• Result GeoPackage: data/03_processed/tech_screening/20260428_tech_screening_32604.gpkg
• CSV mirror: data/03_processed/tech_screening/20260428_tech_screening.csv
• README: data/03_processed/tech_screening/README.md

Screen Techs — Resources

• Notebook: 03_screen_techs.ipynb
• Screening helpers: src/screen_techs.py
• Config exporter: src/export_config.py
• Configuration folder: config/baseline/

Results

• Results slides summarize the two processed outputs.
• Point the audience to the Results pages and the Hawaii OSDS Technology Suitability Analysis Map (Pilot) for the full tables, downloads, and spatial view.

MPAT

Measure	Kauai	Maui	Oahu	Total
Parcels	9,994	7,505	9,725	27,224
Cesspools	13,779	10,337	10,026	34,142

• Output date: 2026-04-28
• CRS: EPSG:32604
• Pilot islands: Maui, Oahu, Kauai

Distribution of depth_to_wt_ft.

Full results

• The full Results, MPAT page includes the remaining summary graphs, the parcel analysis points breakdown, and links to the MPAT GeoPackage, CSV mirror, schema, and pilot web map.

Technology Recommendations

27,224 parcels were screened across 15 endpoints and assigned to 5 output categories.

Output category counts by island.

Full results

• The full Results, Technology Recommendations page includes endpoint pass counts, planning flags, no-primary cases, E01 by island, and links to the screening GeoPackage, CSV mirror, output schema, and pilot web map.

Guide to Key Resources

• Three asset categories: GitHub repo (code, configs, notebooks), Google Drive (raw data and intermediate files), ArcGIS Online (web map and view layers).
• The full handoff site has a dedicated Resources page with the complete directory of links.

Resources overview

Three places to find what:

• GitHub. Code, configuration, notebooks, this documentation site.
• Google Drive. Source data, prepared layers, processed outputs.
• InfoWRRC ArcGIS Online. Published web maps and view layers.

GitHub Repository

https://github.com/cshuler/HiOSDS-TechSuitabilityAnalysis

Shared Google Drive

• Main: https://drive.google.com/drive/folders/0AIA5LcNcOyMjUk9PVA
• Project: https://drive.google.com/drive/folders/1UthygoY0CMMOgB3RCuARWT_sPdnphIdF?usp=drive_link

InfoWRRC ArcGIS Online

• HiOSDS-TechSuitabilityAnalysis content page
• Hawaii OSDS Technology Suitability Analysis Map (Pilot)
• The_Matrix_Group group page

Full resource directory

Questions and next steps

• Pilot scope. Big Island and the smaller islands pending.
• DOH verification. Three thresholds (well_domestic_ft, well_seepage_ft, sfha_flag) await DOH input. See Start Here for the working assumptions.
• Web map. The Hawaii OSDS Technology Suitability Analysis Map (Pilot) is live with current outputs. Future work includes the narrative templates (T01–T11) for property owner communication.