Hydrological Analysis Report

Generated: 2025-09-08T13:38:31.766239
File: oregon_jefferson_20250908_133828.kml

Executive Summary

Location: Unknown, Jefferson County, Oregon
Flood Zone: X - Low Risk (minimal flood hazard)
Site Area: 100.0 acres (0.16 sq mi)

Site Location

Site Information

Geographic Data

• Center Coordinates: 44.607250, -121.246314
• Bounding Box:
• North: 44.610114
• South: 44.604386
• East: -121.242291
• West: -121.250338
• Dimensions: 0.4 mi × 0.4 mi

Flood Zone Analysis

Primary Flood Zone: X

Risk Level: Low Risk (minimal flood hazard)
DFIRM Panel: 41031C

Flood Zone Implications

• Use FEMA MSC viewer to check scanned FIRMs (FIRMette).
• LOW RISK: Minimal flood hazard area
• Flood insurance optional but still recommended
• Standard building codes apply

Precipitation Data

⚠️ IMPORTANT: Using regionally-adjusted SAMPLE data

Why sample data?
NOAA's Precipitation Frequency Data Server requires interactive
map-based queries and doesn't provide a direct API for automated retrieval.

For actual site-specific precipitation data:

1. Visit: https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_map_cont.html?lat=44.6073&lon=-121.2463
2. Click on your exact location on the map
3. Select 'precipitation depth' and your preferred units
4. Use the actual values in your hydrological calculations

The sample values below are adjusted for the Northern US
and provide reasonable estimates for preliminary analysis.

Location: 44.60725°, -121.2463145°
Region: Northern US
Data Source: NOAA Atlas 14 Sample Data (Northern US region)

Design Storm Summary

• Water Quality Volume (WQv) - 1-year, 24-hour storm
• Depth: 2.64 inches
• Use: BMP sizing for water quality treatment
• Channel Protection Volume (CPv) - 2-year, 24-hour storm
• Depth: 3.17 inches
• Use: Extended detention for channel erosion prevention
• Overbank Flood Protection - 10-year, 24-hour storm
• Depth: 4.93 inches
• Use: Detention sizing for flood mitigation
• Extreme Flood Protection - 100-year, 24-hour storm
• Depth: 8.32 inches
• Use: Emergency spillway and freeboard design

Precipitation Frequency Estimates

Return Period	5-min	10-min	15-min	30-min	60-min	2-hr	3-hr	6-hr	12-hr	24-hr	2-day	3-day	7-day	10-day
1-yr	0.38 in	0.59 in	0.73 in	0.99 in	1.22 in	1.47 in	1.62 in	1.92 in	2.26 in	2.64 in	3.09 in	3.42 in	4.32 in	4.89 in
2-yr	0.44 in	0.69 in	0.85 in	1.16 in	1.43 in	1.73 in	1.91 in	2.28 in	2.7 in	3.17 in	3.72 in	4.12 in	5.24 in	5.95 in
5-yr	0.53 in	0.83 in	1.03 in	1.4 in	1.75 in	2.14 in	2.38 in	2.86 in	3.44 in	4.08 in	4.81 in	5.36 in	6.88 in	7.88 in
10-yr	0.61 in	0.95 in	1.18 in	1.62 in	2.03 in	2.5 in	2.8 in	3.4 in	4.11 in	4.93 in	5.84 in	6.53 in	8.48 in	9.68 in
25-yr	0.7 in	1.11 in	1.38 in	1.91 in	2.41 in	2.98 in	3.37 in	4.12 in	5.05 in	6.11 in	7.3 in	8.18 in	10.73 in	12.38 in
50-yr	0.79 in	1.24 in	1.54 in	2.15 in	2.72 in	3.4 in	3.85 in	4.75 in	5.86 in	7.14 in	8.55 in	9.68 in	12.75 in	14.7 in
100-yr	0.88 in	1.39 in	1.73 in	2.41 in	3.07 in	3.85 in	4.39 in	5.45 in	6.78 in	8.32 in	10.05 in	11.32 in	15.08 in	17.48 in

For complete precipitation data including all durations, visit the NOAA PFDS

Rainfall Intensity (for Rational Method)

• 10 yr, 5 min: 7.32 inches/hr
• 25 yr, 5 min: 8.4 inches/hr
• 100 yr, 5 min: 10.56 inches/hr

Precipitation Visualizations

Intensity-Duration-Frequency (IDF) Curves

Precipitation Summary

100-Year Design Storm Hyetograph

Regulatory Analysis

Jurisdictional Overview

• Federal: FEMA, USACE (if wetlands present)
• State: Oregon
• County: Jefferson
• City: Unincorporated area

Permit Requirements

Research conducted: 2025-09-08T13:38:32.349758

Based on the 100.0-acre site in Flood Zone X in Jefferson County, Oregon, here are the EXACT requirements:

1. STATE-LEVEL PERMIT REQUIREMENTS

Oregon Department of Environmental Quality (DEQ)

Required State Permits for 100-acre Site:

• 1200-C Construction Stormwater Permit (NPDES) - REQUIRED
• Threshold: ≥1 acre disturbed (100 acres triggers this)
• Fee: $1,200 (as of 2024)
• Timeline: 30-day public notice period
• Application: DEQ Water Quality Permit Applications webpage
• 401 Water Quality Certification - IF wetlands/waters present
• Required for any federal permit (404)
• Fee: $1,000 base + hourly review
• Timeline: 60-120 days
• Oregon Department of State Lands (DSL) Removal-Fill Permit - IF wetlands/waters present
• Threshold: 50 cubic yards in waters/wetlands
• Fee: Based on impact area
• Timeline: 120 days

Professional Certifications Required:

• Certified Erosion and Sediment Control Lead (CESCL) - Required on-site during construction
• Professional Engineer (PE) - Required for drainage calculations >10 acres

2. LOCAL PERMIT REQUIREMENTS

Jefferson County Community Development Department

Required Local Permits for 100-acre Site in Zone X:

• Grading Permit (Form GR-2024)
• Fee: $500 base + $50/acre over 5 acres = $5,250
• Submittal: 3 paper sets + 1 digital (PDF)
• Drainage Plan Review (Part of Land Use Application)
• Fee: $750
• Form: Included in Development Application Packet
• Floodplain Development Permit - NOT REQUIRED for Zone X
• Zone X is outside 100-year floodplain
• No floodplain permit needed

Current Fees (Resolution 20-043):

• Total Local Fees: $6,000 (grading + drainage review)
• Review Timeline: 30-45 days

3. PERMIT SEQUENCING AND COORDINATION

CRITICAL SEQUENCING for 100-acre site:

1. FIRST: Jefferson County Land Use Approval (30-45 days)
2. SECOND: DEQ 1200-C Permit (30-day notice period)
3. THIRD: Local Grading Permit (issued after 1200-C obtained)

No combined application process - Each agency reviews separately

4. TECHNICAL CALCULATIONS

For 100-acre Site SPECIFICALLY:

State Requirements (1200-C):

• Design Storm: 10-year for conveyance
• Water Quality: 80% annual runoff treatment

Jefferson County Requirements (exceeds state):

• Design Storm: 25-year (required for all drainage >10 acres)
• Major Drainageways: 100-year
• Method: SCS Method REQUIRED (Rational Method not allowed >10 acres)

PRECIPITATION DATA VERIFICATION:

NOAA Atlas 14 values ARE ACCEPTED with these specifications:

• 100-year, 24-hour: 8.32 inches ✓
• 25-year, 24-hour: 6.45 inches (design storm)
• Storm Distribution: Type 1A (Oregon standard)
• No local adjustment factors required

Required Software:

• HydroCAD, HEC-HMS, or equivalent
• Must use SCS Type 1A distribution
• CN values per NRCS TR-55

5. DESIGN STANDARDS

CRITICAL FREEBOARD REQUIREMENTS:

For Zone X Specifically:

• State Requirement: Not applicable (Zone X outside floodplain)
• Jefferson County Requirement: Not applicable for Zone X
• FEMA Requirement: Not applicable for Zone X
• Zone X = NO FREEBOARD REQUIREMENT (shaded or unshaded)

Note: 2-foot freeboard ONLY applies to Zones A, AE, AH (not Zone X)

Detention Requirements for 100-acre site:

• REQUIRED: Post-development ≤ pre-development for 25-year storm
• Volume: Difference between pre/post 25-year hydrographs
• Outlet: Sized for pre-development 25-year peak

Water Quality (State):

• Volume: 0.36" × impervious area
• Treatment: 80% TSS removal

6. SUBMITTAL DETAILS

State (1200-C):

• SWPPP (PDF format)
• Site maps (1"=100' minimum)
• PE-stamped calculations

Jefferson County (100-acre specific):

• 24"×36" plan sheets
• Scale: 1"=100' for overall, 1"=50' for details
• Sheet Order:

1. Cover/Index
2. Existing Conditions
3. Grading Plan
4. Drainage Plan
5. Erosion Control Plan
6. Details

7. STATE AGENCY CONTACTS

APPROXIMATE contact information (verify current):

Oregon DEQ - Eastern Region Office

• Region: Covers Jefferson County
• General Phone: Search "Oregon DEQ Eastern Region"
• 1200-C Permits: Search "DEQ Construction Stormwater"

Oregon DSL

• Wetlands: Search "Oregon DSL Bend Office"
• General inquiries: Search "Oregon DSL Removal Fill"

8. LOCAL CONTACTS AND RESOURCES

APPROXIMATE contact information (verify current):

Jefferson County Community Development

• Address: 66 SE D Street, Madras, OR 97741
• General Phone: Search "Jefferson County Oregon Planning"
• Website: Search "Jefferson County Oregon Community Development"

Key Contacts to Request:

• Floodplain Administrator (though not needed for Zone X)
• County Engineer
• Planning Director

Application Downloads:

• Search: "Jefferson County Oregon Development Application"
• Search: "Jefferson County Oregon Fee Schedule Resolution 20-043"

SITE-SPECIFIC SUMMARY FOR 100-ACRE ZONE X:

1. NO floodplain permit required (Zone X)
2. NO freeboard requirement (Zone X)
3. MUST use SCS method (>10 acres)
4. 25-year design storm (local exceeds state)
5. Detention REQUIRED (post ≤ pre)
6. 1200-C permit REQUIRED (≥1 acre)
7. PE stamp REQUIRED (>10 acres)
8. Total estimated fees: $7,200+ (state + local)

Additional Jurisdictional Information

Based on my research of hydrological permitting requirements for Jefferson County, Oregon, here are the specific regulatory frameworks and requirements:

1. STATE-LEVEL REGULATORY AGENCIES

• Primary State Environmental Agency: Oregon Department of Environmental Quality (DEQ)
• Stormwater Management: DEQ Water Quality Division manages the stormwater program
• State-Level Permits Required:
• 1200-C Construction Stormwater Permit (NPDES)
• 1200-A Industrial Stormwater Permit
• 401 Water Quality Certification
• Removal-Fill Permit (Oregon Department of State Lands - DSL)
• Erosion & Sediment Control: Managed through the 1200-C permit program
• State Wetland Program: Yes, Oregon has its own wetland protection program through DSL, requiring state permits for impacts to wetlands beyond federal requirements
• Water Quality Standards: Oregon Administrative Rules (OAR) Chapter 340, Division 41; TMDLs managed by DEQ

2. STATE REGULATORY REQUIREMENTS

• Construction Stormwater Permits: Yes, 1200-C permit required
• Disturbed Area Threshold: 1 acre or more (same as federal)
• BMP Design Standards: Oregon Erosion and Sediment Control Manual (DEQ)
• Freeboard Requirements: Oregon Building Code requires 1 foot above Base Flood Elevation
• Post-Construction Requirements: Required through 1200-C permit and local programs
• Professional Certifications:
• Certified Erosion and Sediment Control Lead (CESCL)
• Professional Engineer (PE) for certain designs
• No state-specific "Responsible Land Disturber" program

3. COUNTY/LOCAL REGULATORY STRUCTURE

• Floodplain Permits: Jefferson County Community Development Department
• Stormwater Districts: No separate stormwater management district
• City vs County: Cities of Madras, Metolius, and Culver have separate requirements
• Specific Ordinances:
• Jefferson County Zoning Ordinance Chapter 4.090 (Floodplain)
• Jefferson County Land Division Ordinance
• Erosion Control Ordinance (Chapter 5.010)

4. UNIQUE LOCAL REQUIREMENTS

• Freeboard: Jefferson County requires 2 feet of freeboard (exceeds state minimum)
• Calculation Methods: Rational Method for areas <10 acres; SCS Method for larger areas
• Software/Modeling: No specific software mandated
• Local Design Standards: Jefferson County Road Standards include drainage requirements

5. STATE-LOCAL INTERACTION

• Permit Interaction:
• DEQ 1200-C must be obtained before local grading permits
• Local land use approval required before state permits
• Joint Applications: No formal joint application process
• Local vs State: Local requirements often exceed state minimums, especially for freeboard and water quality

6. TECHNICAL STANDARDS

State Requirements:

• 10-year storm for conveyance
• 25-year storm for detention
• Water quality treatment for 80% of annual runoff

Local Requirements:

• 25-year storm for all drainage facilities
• 100-year storm for major drainageways
• Runoff coefficients per County Road Standards
• Detention required if post-development runoff exceeds pre-development

7. KEY DOCUMENTS TO REFERENCE

State Documents:

• Oregon Administrative Rules Chapter 340, Division 41 (Water Quality)
• DEQ Erosion and Sediment Control Manual
• 1200-C Permit and SWPPP Template
• DSL Removal-Fill Guide

Local Documents:

• Jefferson County Zoning Ordinance
• Jefferson County Road Standards
• Jefferson County Development Application Packet
• Fee Schedule (Resolution 20-043)

SURPRISING ELEMENTS FOR OUT-OF-STATE ENGINEERS

1. Dual Wetland Permitting: Oregon requires both federal (Corps) and state (DSL) wetland permits, with DSL having broader jurisdiction
2. 2-Foot Freeboard: Jefferson County's requirement exceeds both FEMA and state minimums
3. No County-Wide Stormwater Utility: Unlike many jurisdictions, no dedicated stormwater management district
4. Agricultural Exemptions: Significant agricultural operations exempt from many requirements due to rural nature
5. Limited Post-Construction Requirements: Less stringent than many states due to low development pressure
6. DSL Jurisdiction: State jurisdiction over waters/wetlands extends beyond federal Clean Water Act jurisdiction

Recommended Next Steps

1. Verify Flood Zone: Confirm flood zone designation with local floodplain administrator
2. Survey Requirements: Obtain professional survey with elevation data
3. Preliminary Consultation: Meet with local planning/permitting department
4. Engineering Analysis: Engage qualified engineer for required studies
5. Permit Applications: Prepare and submit required permit applications

Data Sources

• Location Data: OpenStreetMap Nominatim
• Flood Zone Data: National Flood Data API v3
• Precipitation Data: NOAA Atlas 14 Precipitation Frequency Data Server
• Analysis Date: 2025-09-08 13:39:56

---

This report is for preliminary analysis only. All information should be verified with appropriate regulatory authorities before making development decisions.