40 CFR § 131.48 - Water quality standards to protect aquatic life in the Delaware River.

---
identifier: "/us/cfr/t40/s131.48"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 131.48 - Water quality standards to protect aquatic life in the Delaware River."
title_number: 40
title_name: "Protection of Environment"
section_number: "131.48"
section_name: "Water quality standards to protect aquatic life in the Delaware River."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "D"
subchapter_name: "WATER PROGRAMS"
part_number: "131"
part_name: "WATER QUALITY STANDARDS"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "33 U.S.C. 1251"
regulatory_source: "48 FR 51405, Nov. 8, 1983, unless otherwise noted."
cfr_part: "131"
---


# 131.48 Water quality standards to protect aquatic life in the Delaware River.

(a) *Scope*. (1) The designated use in paragraph (b) of this section applies to river miles 108.4 to 70.0 of the mainstem Delaware River for the States of New Jersey and Pennsylvania.

(2) The aquatic life criteria in paragraph (c) of this section apply to river miles 108.4 to 70.0 of the mainstem Delaware River for the States of Delaware, New Jersey, and Pennsylvania.

(b) *Aquatic life designated use*. The aquatic life designated use is protection and propagation of resident and migratory aquatic life.

(c) *Dissolved oxygen criteria*. The applicable dissolved oxygen criteria are shown in table 1 to this paragraph (c).

Table 1 to Paragraph (**c**)—Dissolved Oxygen Criteria

| Season | Magnitude
(percent oxygen
saturation) | Duration | Exceedance frequency |
| --- | --- | --- | --- |
| Spawning and Larval Development | 66 | Daily Average | 12 Days Cumulative . |
| Juvenile Development | 66 | Daily Average | 12 Days Cumulative . |
|  | 74 | Daily Average | 61 Days Cumulative . |
| Overwintering | 66 | Daily Average | 12 Days Cumulative . |

(d) *Applicability*. (1) The aquatic life designated use in paragraph (b) of this section applies concurrently with other applicable designated uses in New Jersey and Pennsylvania for river miles 108.4 to 70.0 of the mainstem Delaware River.

(2) The dissolved oxygen aquatic life water quality criteria in paragraph (c) of this section are the applicable dissolved oxygen criteria in Delaware, New Jersey, and Pennsylvania for river miles 108.4 to 70.0 of the mainstem Delaware River and apply concurrently with other applicable water quality criteria.

(3) The designated use and criteria established are subject to Delaware's, New Jersey's, and Pennsylvania's general rules of applicability in the same way and to the same extent as are other federally promulgated and State-adopted water quality standards in those States.

[90 FR 46508, Sept. 29, 2025]