Rain Garden¶

Rain garden is a derived concept in the live citations layer, not a standalone BMP Manual chapter. In this corpus, the source-backed basis is small-scale bioretention under BMP Manual Chapter 9.7, used here as the residential- and lot-scale expression of that chapter.

Structured citation evidence for this page lives in the sibling claim manifest.

Overview¶

This page should be read as a practical doorway into Chapter 9.7 rather than as an independent authority. A rain garden uses the same source-backed design family as small-scale bioretention: shallow ponding, soil/media treatment, and either infiltrating or underdrained configurations depending on the actual site conditions.

Source Mapping¶

This route is retained for site navigation, but the live citations layer flags a taxonomy or classification caution for it.

Route caution: Rain Garden is not a separate BMP Manual chapter. It is a lay term for small-scale bioretention (Ch. 9.7). All design criteria should cite 9.7 with a note explaining the equivalence.
Route type: derived
2023 source bundle: Chapter 9.7 (2023_BMP_9_7) - Small-Scale Bioretention Systems (lay term: rain garden)
2026 source bundle: Chapter 9.7 (2026_BMP_9_7) - Small-Scale Bioretention Systems (lay term: rain garden)
Source-basis note: Rain garden is not a BMP Manual chapter. It is a common name for small-scale bioretention (Ch. 9.7). All design criteria must cite 9.7.

Key verified claims already tied to this page manifest: - Rain garden is a derived concept anchored to Chapter 9.7 rather than a standalone source chapter. - Rain-garden scale limits stay tied to the 2.5-acre Chapter 9.7 bioretention threshold. - Recharge use stays tied to the infiltrating Chapter 9.7 configuration.

Design Criteria¶

The reconciled design criteria below come from the live crosswalk and page-level claim set, not from the older narrative snapshot.

This route does not have a dedicated parameter table in the crosswalk, so the controlling criteria stay tied to the verified claims and canonical source-bundle mapping below.

Source-backed criteria that still control this route: - Rain garden is a derived concept anchored to Chapter 9.7 rather than a standalone source chapter. - Rain-garden scale limits stay tied to the 2.5-acre Chapter 9.7 bioretention threshold. - Recharge use stays tied to the infiltrating Chapter 9.7 configuration.

Siting Constraints¶

The correct siting questions are the same ones used for small-scale bioretention:

whether the site investigation supports infiltration into subsoil
whether SHWT separation and hydraulic-impact review support the intended configuration
whether the project is actually using a small lot-scale bioretention feature rather than stretching the label to a different BMP type

Maintenance¶

Maintenance stays tied to the Chapter 9.7 performance indicators:

watch ponding and drain time after storms
keep inlets, pretreatment features, and overflow paths clear
preserve vegetation and avoid compaction of the soil/media surface

Source Bundles¶

Use these source bundles when checking the live extracted text or paired OCR evidence:

2023 bundle: Chapter 9.7 (2023_BMP_9_7) - Small-Scale Bioretention Systems (lay term: rain garden)
2026 bundle: Chapter 9.7 (2026_BMP_9_7) - Small-Scale Bioretention Systems (lay term: rain garden)