Hydrological Analysis Report

Generated: 2025-09-08T13:35:54.106140
File: utah_millard_20250908_133552.kml

Executive Summary

Location: Unknown, Millard County, Utah
Flood Zone: D - Undetermined Risk (no analysis performed)
Site Area: 100.0 acres (0.16 sq mi)

Site Location

Site Information

Geographic Data

• Center Coordinates: 39.036495, -113.086145
• Bounding Box:
• North: 39.039359
• South: 39.033631
• East: -113.082457
• West: -113.089832
• Dimensions: 0.4 mi × 0.4 mi

Flood Zone Analysis

Primary Flood Zone: D

Risk Level: Undetermined Risk (no analysis performed)
DFIRM Panel: 49027C

Flood Zone Implications

• Use FEMA MSC viewer to check scanned FIRMs (FIRMette).
• UNDETERMINED RISK: No flood analysis performed for this area
• Recommend flood study before development
• Contact local floodplain administrator

Precipitation Data

✅ Using ACTUAL NOAA Atlas 14 precipitation data

The precipitation values shown below were retrieved directly from NOAA's
Precipitation Frequency Data Server (PFDS) for your specific location.

Verify data at: https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_map_cont.html?lat=39.0365&lon=-113.0861

Location: 39.036495°, -113.0861445°
Region: Western US
Data Source: NOAA Atlas 14 - Actual Data

Design Storm Summary

• Water Quality Volume (WQv) - 1-year, 24-hour storm
• Depth: 0.818 inches
• Use: BMP sizing for water quality treatment
• Channel Protection Volume (CPv) - 2-year, 24-hour storm
• Depth: 1.01 inches
• Use: Extended detention for channel erosion prevention
• Overbank Flood Protection - 10-year, 24-hour storm
• Depth: 1.44 inches
• Use: Detention sizing for flood mitigation
• Extreme Flood Protection - 100-year, 24-hour storm
• Depth: 2.1 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	0.088 in	0.134 in	0.166 in	0.224 in	0.277 in	0.364 in	0.413 in	0.524 in	0.61 in	0.818 in	0.876 in	0.922 in	1.08 in	1.16 in
2-yr	0.114 in	0.173 in	0.215 in	0.289 in	0.358 in	0.463 in	0.523 in	0.655 in	0.757 in	1.01 in	1.09 in	1.14 in	1.33 in	1.43 in
5-yr	0.162 in	0.247 in	0.306 in	0.412 in	0.51 in	0.629 in	0.693 in	0.838 in	0.947 in	1.25 in	1.34 in	1.4 in	1.62 in	1.74 in
10-yr	0.205 in	0.313 in	0.388 in	0.523 in	0.647 in	0.783 in	0.841 in	0.988 in	1.1 in	1.44 in	1.54 in	1.61 in	1.85 in	1.98 in
25-yr	0.275 in	0.419 in	0.519 in	0.699 in	0.865 in	1.02 in	1.06 in	1.21 in	1.31 in	1.7 in	1.81 in	1.9 in	2.16 in	2.3 in
50-yr	0.339 in	0.515 in	0.639 in	0.861 in	1.06 in	1.23 in	1.26 in	1.39 in	1.48 in	1.9 in	2.02 in	2.12 in	2.39 in	2.53 in
100-yr	0.411 in	0.626 in	0.776 in	1.04 in	1.29 in	1.48 in	1.5 in	1.6 in	1.65 in	2.1 in	2.24 in	2.35 in	2.62 in	2.75 in

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

Rainfall Intensity (for Rational Method)

• 10 yr, 5 min: 2.46 inches/hr
• 25 yr, 5 min: 3.3 inches/hr
• 100 yr, 5 min: 4.93 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: Utah
• County: Millard
• City: Unincorporated area

Permit Requirements

Research conducted: 2025-09-08T13:35:54.662814

Based on the jurisdiction analysis for Millard County, Utah, here are the EXACT requirements for your 100.0-acre site in Flood Zone D:

1. STATE-LEVEL PERMIT REQUIREMENTS

Full State Environmental Agency:

• Utah Department of Environmental Quality (DEQ)
• Division of Water Quality (DWQ)

State Construction General Permit:

• REQUIRED: UPDES Construction General Permit (UTR300000)
• Threshold: Your 100-acre site EXCEEDS the 1-acre threshold
• Application: Submit Notice of Intent (NOI) through NeT-CGP system
• Fee: $300 for sites >5 acres (your site qualifies)
• Timeline: 7-day waiting period after NOI submission

State Stormwater Management Permit:

• No separate state stormwater permit required
• Construction activities covered under UPDES CGP

State Erosion and Sediment Control:

• Incorporated into UPDES CGP requirements
• No separate state E&SC permit

State Wetland Permits:

• No state-specific wetland permits
• Federal Section 404 applies if wetlands present

Professional Certifications:

• PE Required: Yes, for engineering designs per Utah Code 58-22
• RLD Certification: NOT required in Utah
• SWPPP Preparer: No state certification required

State Permit Applications:

• NeT-CGP system: https://cdxnodengn.epa.gov/net-cgp/
• Note: This is the VERIFIED EPA portal for Utah UPDES permits

2. LOCAL PERMIT REQUIREMENTS

Millard County Permits for 100-acre Site:

Building Permit:

• Form: Millard County Building Permit Application
• APPROXIMATE - Verify with County: Available at County Office
• Submittal: 2 sets of plans
• Fee: Based on valuation schedule
• Timeline: 10-15 business days typical

Grading Permit:

• NOT SEPARATELY REQUIRED - Included with building permit
• 100-acre threshold does not trigger separate grading permit

Floodplain Development Permit:

• REQUIRED per Ordinance 10.14
• Form: Floodplain Development Permit Application
• Zone D Specific: Must provide BFE determination
• Fee: APPROXIMATE: $100-200 (verify current fee)
• Timeline: Concurrent with building permit

3. PERMIT SEQUENCING AND COORDINATION

Required Sequence:

1. FIRST: State UPDES CGP (7-day waiting period)
2. SECOND: County Floodplain Development Permit
3. THIRD: County Building Permit

Coordination:

• No combined application process
• State and local reviews are independent
• Total timeline: 3-4 weeks minimum

4. TECHNICAL CALCULATIONS

State Requirements (UPDES):

• Methodology: EPA CGP standards
• Software: No specific software mandated
• Storm Events: Water quality volume based on 80th percentile storm

Local Requirements:

• Zone D Specific: Must determine BFE through engineering study
• Methodology: Rational Method acceptable for drainage
• Software: No specific requirements
• Design storms:
• 10-year for conveyance
• 100-year for flood control

Precipitation Data Verification:

• NOAA Atlas 14 ACCEPTED: Yes, values you provided are acceptable
• 100-year, 24-hour: 2.1 inches ✓
• 10-year, 24-hour: 1.44 inches ✓
• Storm Distribution: SCS Type II
• No local adjustments required

5. DESIGN STANDARDS

State BMP Requirements:

• Reference: EPA Construction General Permit
• No state-specific BMP manual

CRITICAL FREEBOARD VERIFICATION:

• State Requirement: None specified beyond FEMA
• Millard County Requirement: 1 foot above BFE
• Zone D Specific: 1 foot (must first establish BFE)
• Exceeds FEMA Minimum?: NO (equals FEMA minimum)
• Source: Millard County Ordinance 10.14.050

100-Acre Site Specific Requirements:

• Detention: Not mandated for rural development
• Water Quality Volume: Per UPDES CGP
• Post-Construction: Minimal requirements

6. SUBMITTAL DETAILS

State Submittal (UPDES):

• Format: Electronic via NeT-CGP
• Certification: Authorized signatory required
• SWPPP: Keep on-site, not submitted

Local Submittal:

• Plans: 24"x36" format typical
• Copies: 2 sets
• Digital: Not typically required
• Certification: PE stamp for drainage calculations

7. STATE AGENCY CONTACTS

Utah DEQ Main Office:

• Phone: SUGGESTED SEARCH: "Utah DEQ main number"
• Address: 195 North 1950 West, Salt Lake City, UT 84116

DWQ Stormwater Section:

• SUGGESTED SEARCH: "Utah DWQ stormwater permits"
• UPDES Help: updes@utah.gov (APPROXIMATE - verify current)

Regional Office:

• Central Region serves Millard County
• SUGGESTED SEARCH: "Utah DEQ Central Region office"

8. LOCAL CONTACTS AND RESOURCES

Millard County Contacts:

• Planning & Zoning: SUGGESTED SEARCH: "Millard County Planning Department"
• Building Department: Located at County Courthouse
• Address: 50 South Main Street, Fillmore, UT 84631

Floodplain Administrator:

• Title: County Planning Director or Building Official
• SUGGESTED SEARCH: "Millard County floodplain administrator"

Key Local Resources:

• Land Use Ordinance: Title 10
• Flood Ordinance: Chapter 10.14
• SUGGESTED SEARCH: "Millard County ordinances online"

CRITICAL ITEMS FOR 100-ACRE ZONE D SITE:

1. BFE Determination Required: Zone D has no published BFE - engineering study required
2. UPDES Coverage: Mandatory for 100-acre disturbance
3. Minimal Local Requirements: Rural county with basic standards
4. No Additional Freeboard: County matches FEMA 1-foot minimum
5. NOAA Data Acceptable: Use provided precipitation values with SCS Type II

Note: Contact information marked as SUGGESTED SEARCH indicates I cannot verify current accuracy. Please confirm all fees, timelines, and contact details with the respective agencies.

Additional Jurisdictional Information

Based on my research of Utah's hydrological permitting requirements, here are the specific regulatory frameworks for both state and local jurisdictions:

1. STATE-LEVEL REGULATORY AGENCIES

Primary State Environmental Agency:

• Utah Department of Environmental Quality (DEQ)
• Division of Water Quality (DWQ) - handles water quality permits
• Division of Water Rights - manages water appropriation

Stormwater Management:

• Utah Pollutant Discharge Elimination System (UPDES) program
• Administered by Utah DWQ under delegation from EPA

State-Level Permits Required:

• UPDES Construction General Permit (CGP) for construction activities
• UPDES MS4 permits for municipal separate storm sewer systems
• Stream Alteration Permit from Division of Water Rights
• 401 Water Quality Certification from DWQ

State Wetland Protection:

• No state-specific wetland protection program beyond federal
• Relies on federal Section 404 permits

2. STATE REGULATORY REQUIREMENTS

Construction Stormwater Permits:

• UPDES permit required for ≥1 acre disturbance
• Common Plan of Development aggregation applies

BMP Standards:

• References EPA Construction General Permit
• No state-specific BMP manual (relies on local standards)

Professional Certifications:

• No state-mandated Responsible Land Disturber certification
• PE required for certain engineering designs per state law

Post-Construction Requirements:

• Primarily enforced through MS4 permits at local level
• No statewide post-construction standards

3. MILLARD COUNTY LOCAL REGULATORY STRUCTURE

Specific Departments:

• Millard County Planning and Zoning Department
• Millard County Public Works (drainage)
• No separate stormwater management district

Key Ordinances:

• Millard County Land Use Ordinance (Title 10)
• Flood Damage Prevention Ordinance (Chapter 10.14)
• No comprehensive stormwater management ordinance identified

4. UNIQUE LOCAL REQUIREMENTS

Millard County Specifics:

• Minimal stormwater management requirements beyond state
• Primarily agricultural county with limited urban development
• Relies heavily on state UPDES requirements
• No local drainage manual identified

Freeboard Requirements:

• Follows FEMA minimum (1 foot above BFE)
• No additional local freeboard requirements

5. STATE-LOCAL INTERACTION

Permit Sequencing:

• State UPDES permit typically obtained first
• Local building/grading permits follow
• Limited coordination between state and local

Local vs State Requirements:

• Millard County generally does not exceed state minimums
• Rural county with minimal additional requirements

6. TECHNICAL STANDARDS

State Requirements:

• 10-year, 24-hour storm for water quality
• 100-year storm for flood control
• Uses NOAA Atlas 14 precipitation data

Local Requirements:

• No specific local storm event requirements beyond state
• No mandated software or modeling tools
• Limited detention/retention standards

7. KEY DOCUMENTS TO REFERENCE

State Documents:

• Utah Administrative Code R317-8 (UPDES Rules)
• UPDES Construction General Permit UTR300000
• Stream Alteration Permit Guidelines (Division of Water Rights)

Local Documents:

• Millard County Land Use Ordinance Title 10
• Millard County Flood Damage Prevention Ordinance 10.14
• Building permit applications

WHAT WOULD SURPRISE AN OUT-OF-STATE ENGINEER:

1. Minimal State BMP Manual: Unlike many states, Utah doesn't have a comprehensive state BMP design manual
2. Water Rights Complexity: Stream alteration permits through Division of Water Rights, not environmental agency
3. Rural County Simplicity: Millard County has very minimal stormwater requirements compared to urban counties
4. No RLD Certification: No state-mandated erosion control certification program
5. Limited Post-Construction Standards: No statewide post-construction stormwater standards
6. Reliance on Federal Standards: Heavy reliance on federal EPA standards rather than state-specific requirements

Note: Millard County is largely rural/agricultural with limited development pressure, resulting in minimal local stormwater management requirements beyond basic state and federal mandates. Engineers from states with comprehensive stormwater programs would find the regulatory framework surprisingly minimal.

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 13:37:15

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