2.9 Clean Water Act Permitting & NEPA Review

Landscape architectural site design does not operate in a regulatory vacuum. A landscape architect who prepares grading plans, alters riverbanks, fills low areas, impacts tree stands, or works along coastlines must navigate an interlocking web of federal, state, and municipal environmental statutes.

Failing to anticipate required environmental permits routinely halts construction, exposes clients to civil and criminal penalties, and risks enforcement orders requiring expensive site restoration. On the CLARB LARE, candidates must understand not only the statutory triggers and governing agencies but also the sequential permitting workflows required for project approvals.

---

Clean Water Act (CWA) Permitting Framework

Enacted in 1972, the federal Clean Water Act (CWA) establishes the statutory foundation for protecting the chemical, physical, and biological integrity of the nation's waters. The Act asserts federal jurisdiction over Waters of the United States (WOTUS), which encompasses navigable rivers, territorial seas, interstate waters, natural lakes, perennial and intermittent tributaries, and adjacent wetlands.

Clean Water Act (CWA) Permitting Interrelationships
+-------------------------------------------------------------------------+
|                        CLEAN WATER ACT (CWA)                            |
+-------------------------------------------------------------------------+
          │                                    │
          ▼                                    ▼
+-----------------------+            +-----------------------+
|      SECTION 404      |            |      SECTION 402      |
| Dredge & Fill in WOTUS|            |   NPDES Stormwater    |
|  Administered by USACE|            | Administered by EPA / |
|   (with EPA oversight)|            | Authorized State Dept |
+-----------------------+            +-----------------------+
          │                                    │
          ▼                                    ▼
+-----------------------+            +-----------------------+
|      SECTION 401      |            |         SWPPP         |
| State Water Quality   |            |  Stormwater Pollution |
|     Certification     |            |    Prevention Plan    |
|  (Mandatory state     |            |  (Mandatory for site  |
|  approval for 404 IP) |            |  disturbance >= 1 ac) |
+-----------------------+            +-----------------------+

Section 404: Dredge and Fill Permitting

Section 404 regulates the placement of dredged or fill material into Waters of the United States, including jurisdictional wetlands. Examples of regulated activities include site grading that pushes soil into a wetland, constructing roadway embankments across streams, placing riprap bank stabilization, and excavating stormwater basins within wetland buffers.

• Administering Agencies: The U.S. Army Corps of Engineers (USACE) issues Section 404 permits. The Environmental Protection Agency (EPA) establishes environmental guidelines, co-enforces regulations, and maintains final veto authority under Section 404(c).
• Permit Types:
  1. Nationwide Permits (NWPs): General permits issued on a 5-year cycle for activities with minimal individual and cumulative adverse environmental effects. Common NWPs utilized by landscape architects include NWP 14 (Linear Transportation Projects, such as roads and trails crossing streams) and NWP 42 (Recreational Facilities, such as park paths, golf courses, and sports fields). NWPs typically carry strict impact ceilings (often ≤ 0.5 acre of wetland fill or 300 linear feet of stream bed) and require a Pre-Construction Notification (PCN) to the USACE District Engineer.
  2. Individual Permits (IP): Required for projects exceeding NWP thresholds or involving complex, high-impact activities. Individual permits require a formal public notice, agency coordination, comprehensive environmental review, and an alternatives analysis.

The Section 404(b)(1) Guidelines & Mitigation Hierarchy

To receive an Individual Section 404 permit, the applicant must satisfy the strict 404(b)(1) Guidelines, proving that the proposed design is the Least Environmentally Damaging Practicable Alternative (LEDPA). The applicant must strictly follow the three-step mitigation sequencing hierarchy:

1. Avoidance: Demonstrate that no practicable alternative exists that avoids wetland fill entirely (e.g., relocating a parking structure to upland areas).
2. Minimization: Redesign site features to reduce unavoidable impacts (e.g., steepening engineered slopes, utilizing retaining walls, or spanning streams with boardwalks rather than installing culverts).
3. Compensatory Mitigation: Offset all remaining unavoidable wetland losses by restoring, creating, enhancing, or preserving wetlands. Ratios are determined by the USACE based on wetland quality (typically 1.5:1 to 3:1 or higher):
   • Mitigation Banks: The preferred option; applicants purchase credits from an approved third-party commercial wetland mitigation bank within the same hydrologic watershed.
   • In-Lieu Fee (ILF) Programs: The applicant pays a fee to a designated public agency or conservation non-profit that pools funds to execute large-scale watershed restoration.
   • Permittee-Responsible Mitigation (PRM): The applicant designs, permits, constructs, monitors (typically for 5 years), and perpetually maintains a replacement wetland on or off the project site.

Section 401: State Water Quality Certification

Under Section 401, a federal license or permit (such as a USACE 404 permit) cannot be issued until the state environmental protection agency certifies that the proposed discharge will comply with all state water quality standards. This provides states with statutory veto power over federal Section 404 permits.

Section 402: NPDES Stormwater Permitting & the SWPPP

Section 402 establishes the National Pollutant Discharge Elimination System (NPDES), which regulates point-source discharges of pollutants into surface waters. In almost all states, the EPA delegates NPDES authority to state environmental departments.

• Construction General Permit (CGP): Mandated for any construction activity (clearing, grading, excavating, stockpiling) that results in total land disturbance of 1.0 acre or greater, or disturbs less than 1.0 acre if part of a larger common plan of development.
• Stormwater Pollution Prevention Plan (SWPPP): Before breaking ground, the developer and landscape architect must formulate a comprehensive site-specific SWPPP. Key required SWPPP elements include:
  • Identification of pollutant sources and receiving surface waters.
  • A detailed construction sequence and phasing plan to minimize the area of bare soil exposed at any given time.
  • Structural Erosion and Sediment Controls (ESC): silt fences, straw wattles, check dams, sediment basins (mandatory for drainage areas ≥ 10 acres), and stabilized rock construction entrances (track-out control pads).
  • Stabilization requirements: temporary seeding and hydromulch on disturbed areas left unworked for more than 14 days (reduced to 7 days in sensitive watersheds).
  • Weekly written inspection reports and inspections within 24 hours of any 0.25-inch rainfall event.
• MS4 Compliance: Municipal Separate Storm Sewer Systems (MS4) Phase I and Phase II regulations compel municipalities to enforce post-construction stormwater management ordinances requiring low-impact development (LID) and green infrastructure (bioretention, permeable pavers, bioswales) to match pre-development hydrology.

---

National Environmental Policy Act (NEPA)

Enacted in 1969, the National Environmental Policy Act (NEPA) is the foundational "environmental charter" of the United States. NEPA applies to all major federal actions—defined as any project planned, funded, constructed, or permitted by a federal agency (e.g., federal highway funding, HUD housing grants, USACE 404 permits, National Park Service projects).

Three Tiers of NEPA Environmental Review
                         [PROPOSED PROJECT / FEDERAL ACTION]
                                          │
               ┌──────────────────────────┼──────────────────────────┐
               ▼                          ▼                          ▼
      +------------------+      +------------------+      +------------------+
      |   TIER 1: CATEX  |      |    TIER 2: EA    |      |   TIER 3: EIS    |
      |  Categorical     |      |  Environmental   |      |  Environmental   |
      |   Exclusion      |      |   Assessment     |      | Impact Statement |
      +------------------+      +------------------+      +------------------+
               │                          │                          │
        (No significant            (Concise analysis          (Known major
          effects)                  of potential               significant
               │                     impacts)                   impacts)
               ▼                          │                          │
         [NO FURTHER]              ┌──────┴──────┐                   ▼
                                   ▼             ▼              [Public Scoping]
                               [FONSI]     [EIS REQUIRED]            │
                                                                [Draft EIS (DEIS)]
                                                                     │
                                                                [Final EIS (FEIS)]
                                                                     │
                                                                     ▼
                                                                [Record of
                                                              Decision (ROD)]

The Three Tiers of NEPA Review

1. Categorical Exclusion (CATEX / CE): Applied to predefined categories of actions that federal agency regulations have established do not individually or cumulatively have a significant effect on the human environment. Examples include resurfacing an existing asphalt trail, installing standard site furnishings, or routine maintenance of existing park utilities. No formal environmental document is required beyond an administrative checklist.
2. Environmental Assessment (EA): A concise public document prepared when it is unclear whether an action will cause significant environmental impacts. An EA evaluates the project's purpose and need, alternatives, and environmental consequences. An EA concludes with one of two legal outcomes:
   • FONSI (Finding of No Significant Impact): The agency documents that the project will not cause significant environmental degradation; NEPA review is complete.
   • Determination to Prepare an EIS: The EA reveals significant, unmitigable environmental impacts, triggering a full Environmental Impact Statement.
3. Environmental Impact Statement (EIS): A comprehensive, rigorous multidisciplinary document mandated for actions significantly affecting the quality of the human environment (e.g., a major interstate highway corridor, new dam, or regional airport runway). The process includes a Notice of Intent (NOI), public Scoping, Draft EIS (DEIS), a mandatory 45-day public comment period, a Final EIS (FEIS) responding to all public comments, and concludes with a legally binding Record of Decision (ROD) signed by the lead agency.

Key Requirement: Every EIS must rigorously analyze a range of reasonable alternatives, including the mandatory "No Action" alternative, which serves as the environmental baseline against which all proposed build alternatives are evaluated.

---