Hydrological Analysis Report

Generated: 2025-09-08T13:27:21.766172
File: california_kings_20250908_132720.kml

Executive Summary

Location: Unknown, Kings County, California
Flood Zone: A - High Risk - Special Flood Hazard Area (1% annual chance)
Site Area: 100.0 acres (0.16 sq mi)

Site Location

Site Information

Geographic Data

• Center Coordinates: 36.022025, -119.754621
• Bounding Box:
• North: 36.024889
• South: 36.019160
• East: -119.751080
• West: -119.758163
• Dimensions: 0.4 mi × 0.4 mi

Flood Zone Analysis

Primary Flood Zone: A

Risk Level: High Risk - Special Flood Hazard Area (1% annual chance)
DFIRM Panel: 06031C

Flood Zone Implications

• ⚠️ HIGH RISK: Property is in Special Flood Hazard Area (SFHA)
• Flood insurance is MANDATORY for federally-backed mortgages
• Floodplain development permit required for any construction

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=36.0220&lon=-119.7546

Location: 36.0220245°, -119.7546215°
Region: Western US
Data Source: NOAA Atlas 14 - Actual Data

Design Storm Summary

• Water Quality Volume (WQv) - 1-year, 24-hour storm
• Depth: 0.859 inches
• Use: BMP sizing for water quality treatment
• Channel Protection Volume (CPv) - 2-year, 24-hour storm
• Depth: 1.14 inches
• Use: Extended detention for channel erosion prevention
• Overbank Flood Protection - 10-year, 24-hour storm
• Depth: 1.86 inches
• Use: Detention sizing for flood mitigation
• Extreme Flood Protection - 100-year, 24-hour storm
• Depth: 3.14 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	0.066 in	0.094 in	0.114 in	0.156 in	0.219 in	0.323 in	0.398 in	0.536 in	0.683 in	0.859 in	1.04 in	1.15 in	1.46 in	1.58 in
2-yr	0.086 in	0.123 in	0.149 in	0.204 in	0.286 in	0.414 in	0.509 in	0.687 in	0.892 in	1.14 in	1.38 in	1.51 in	1.9 in	2.05 in
5-yr	0.115 in	0.164 in	0.199 in	0.273 in	0.382 in	0.545 in	0.668 in	0.902 in	1.18 in	1.53 in	1.84 in	2.02 in	2.53 in	2.71 in
10-yr	0.14 in	0.201 in	0.243 in	0.333 in	0.467 in	0.66 in	0.807 in	1.09 in	1.43 in	1.86 in	2.24 in	2.46 in	3.08 in	3.3 in
25-yr	0.178 in	0.256 in	0.309 in	0.424 in	0.594 in	0.831 in	1.01 in	1.36 in	1.8 in	2.34 in	2.82 in	3.1 in	3.88 in	4.15 in
50-yr	0.211 in	0.302 in	0.365 in	0.501 in	0.702 in	0.976 in	1.19 in	1.6 in	2.1 in	2.72 in	3.3 in	3.63 in	4.54 in	4.86 in
100-yr	0.247 in	0.354 in	0.428 in	0.586 in	0.821 in	1.14 in	1.38 in	1.85 in	2.42 in	3.14 in	3.82 in	4.21 in	5.26 in	5.62 in

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

Rainfall Intensity (for Rational Method)

• 10 yr, 5 min: 1.68 inches/hr
• 25 yr, 5 min: 2.14 inches/hr
• 100 yr, 5 min: 2.96 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: California
• County: Kings
• City: Unincorporated area

Permit Requirements

Research conducted: 2025-09-08T13:27:22.358114

SITE-SPECIFIC HYDROLOGICAL PERMITTING REQUIREMENTS

100.0-Acre Site in Flood Zone A, Kings County, California

1. STATE-LEVEL PERMIT REQUIREMENTS

Primary State Environmental Agency:

• California State Water Resources Control Board (SWRCB)
• Central Valley Regional Water Quality Control Board (Region 5)

REQUIRED STATE PERMITS FOR THIS 100-ACRE ZONE A SITE:

A. Construction General Permit (CGP)

• Permit Name: NPDES General Permit for Storm Water Discharges Associated with Construction and Land Disturbance Activities
• Order Number: 2022-0057-DWQ (effective September 1, 2023)
• Threshold: REQUIRED - Site exceeds 1-acre disturbance threshold
• Risk Level Determination: Likely Risk Level 2 or 3 due to 100-acre size
• Professional Requirements:
• Qualified SWPPP Developer (QSD) - REQUIRED for Risk Level 2/3
• Qualified SWPPP Practitioner (QSP) - REQUIRED during construction
• Fees: $1,828 annual fee + $1,372 NOI processing (2024 rates)
• Timeline: 7-day waiting period after NOI submittal
• Application: Submit through SMARTS online system only

B. 401 Water Quality Certification

• Required if: Federal permit needed (404, Rivers & Harbors Act)
• Agency: Central Valley RWQCB
• Fee: Based on project impact area (100 acres = approximately $35,000-50,000)
• Timeline: 60-120 days

C. Waste Discharge Requirements (WDR)

• Required for: Permanent stormwater discharges not covered by MS4
• Specific to Zone A: May require additional analysis for flood-related discharges

2. LOCAL PERMIT REQUIREMENTS

KINGS COUNTY SPECIFIC PERMITS FOR 100-ACRE ZONE A SITE:

A. Grading Permit

• Official Name: Kings County Grading Permit
• Form: Available at Community Development Agency
• Submittal Requirements:
• 3 sets of plans (24"x36")
• Digital PDF submittal
• Grading plan at 1"=40' or 1"=50' scale
• SWPPP copy
• Soils report
• Fee: $2,847 base + $142 per acre over 5 acres = $16,362 (2024 rates)
• Review Timeline: 30-45 days

B. Floodplain Development Permit

• Official Name: Floodplain Development Permit
• Authority: Kings County Code Chapter 9.36
• REQUIRED: YES - Site is in Zone A
• Form Number: FDP-2024 (verify current version)
• Specific Requirements for Zone A:
• Base Flood Elevation determination required
• Hydraulic analysis for 100-acre development
• No-rise certification
• Fee: $1,500 + engineering review costs
• Timeline: 45-60 days

C. Improvement Plan Review

• Required for: All drainage improvements
• Submittal: 3 sets + digital
• Fee: Time and materials (estimate $15,000-25,000)

3. PERMIT SEQUENCING AND COORDINATION

MANDATORY SEQUENCE FOR THIS SITE:

1. First: State CGP Coverage (NOI through SMARTS)
2. Second: County Floodplain Development Permit
3. Third: County Grading Permit
4. Fourth: Building permits (if applicable)

Coordination Requirements:

• No combined application process
• County requires proof of state CGP before grading permit
• State and local reviews run independently
• Total timeline: 60-90 days minimum

4. TECHNICAL CALCULATIONS

STATE REQUIREMENTS (CGP):

• Methodology: Risk-based approach
• Software: No specific requirement
• Storm Events:
• 2-year, 24-hour for Risk Level 1
• 10-year, 24-hour for Risk Level 2
• 25-year, 24-hour for Risk Level 3

KINGS COUNTY REQUIREMENTS FOR 100-ACRE ZONE A SITE:

• Methodology: Modified Rational Method (up to 640 acres)
• Software Accepted:
• HEC-RAS (current version 6.3.1)
• HEC-HMS
• StormCAD
• Required Storm Events:
• 10-year for local drainage design
• 100-year for Zone A flood analysis
• Precipitation Data:
• NOAA Atlas 14 ACCEPTED: YES, with verification
• 100-year, 24-hour: 3.14 inches (ACCEPTED)
• 10-year, 24-hour: 1.86 inches (ACCEPTED)
• Storm Distribution: SCS Type II (24-hour)
• Time of Concentration: SCS Method or Kirpich
• Runoff Coefficients: Per County Improvement Standards Table 3-2

5. DESIGN STANDARDS

STATE BMP REQUIREMENTS:

• CASQA BMP Handbooks (current edition)
• CGP Attachment C - Risk Level 2/3 Requirements

KINGS COUNTY SPECIFIC REQUIREMENTS FOR ZONE A:

CRITICAL FREEBOARD VERIFICATION:

• State Requirement: No specific freeboard mandate in CGP
• Kings County Requirement: 1.0 feet above BFE
• For Zone A Specifically: 1.0 feet MINIMUM
• Exceeds FEMA Minimum? NO (equals FEMA minimum)
• Source: Kings County Code Section 9.36.160(A)(1)

Additional Zone A Requirements:

• Lowest floor elevation 1 foot above BFE
• Elevation Certificate required
• Foundation design for flood forces
• Detention: Match pre-development peaks for 10 and 100-year
• Water Quality Volume: 85th percentile storm

6. SUBMITTAL DETAILS

STATE SUBMITTAL (THROUGH SMARTS):

• Electronic only
• PDF format for all documents
• QSD certification required
• PE stamp on technical reports

KINGS COUNTY SUBMITTAL FOR 100-ACRE ZONE A:

• Plans: 24"x36" (3 hard copies + PDF)
• Reports: 8.5"x11" bound (2 copies + PDF)
• Required order:

1. Cover sheet with vicinity map
2. Existing conditions
3. Grading plan
4. Drainage plan
5. Erosion control plan
6. Details

• PE stamp required on all sheets
• Digital format: PDF (individual sheets under 25MB)

7. STATE AGENCY CONTACTS

NOTICE: Contact information should be verified as it may change:

State Water Resources Control Board:

• Main Office: (916) 341-5250
• Storm Water Section: (866) 563-3107
• Website: waterboards.ca.gov
• SMARTS Help Desk: smarts@waterboards.ca.gov

Central Valley Regional Water Board:

• Fresno Office: (559) 445-5116
• Address: 1685 E Street, Fresno, CA 93706
• 401 Certification: (559) 445-5137

8. LOCAL CONTACTS AND RESOURCES

NOTICE: Verify current contact information:

Kings County Floodplain Administrator:

• Department: Public Works
• Phone: (559) 852-2670
• Address: 1400 W. Lacey Blvd, Hanford, CA 93230

Kings County Community Development:

• Planning Division: (559) 852-2665
• Building Division: (559) 852-2665
• Email: planning@co.kings.ca.us

Key Documents Available Online:

• Kings County Code: kingscounty.com
• Improvement Standards: Contact Public Works
• Fee Schedule: Updated annually, request current version

CRITICAL NOTES FOR THIS 100-ACRE ZONE A SITE:

1. Base Flood Elevation must be determined by engineer since Zone A is approximate
2. Hydraulic analysis required to show no adverse impact
3. Agricultural drainage coordination likely required
4. Groundwater depth verification essential for detention design
5. San Joaquin Valley Air District dust permit also required

Additional Jurisdictional Information

HYDROLOGICAL PERMITTING REQUIREMENTS - KINGS COUNTY, CALIFORNIA

1. STATE-LEVEL REGULATORY AGENCIES

Primary State Environmental Agency:

• California Environmental Protection Agency (CalEPA)
• State Water Resources Control Board (SWRCB) - primary water quality authority
• Regional Water Quality Control Board (RWQCB) - Central Valley Region (Region 5) covers Kings County

Stormwater Management Program:

• California has a comprehensive statewide stormwater program administered by SWRCB
• National Pollutant Discharge Elimination System (NPDES) program delegated to California

State-Level Permits Required:

• Construction General Permit (CGP) - Order No. 2009-0009-DWQ as amended
• Industrial General Permit (IGP) for industrial facilities
• Small MS4 General Permit for municipalities
• 401 Water Quality Certification for federal permits

Erosion and Sediment Control:

• Statewide Construction General Permit includes comprehensive erosion control requirements
• Risk-based approach with three risk levels based on project location and characteristics

State Wetland Protection:

• Porter-Cologne Water Quality Control Act provides broader wetland protection than federal
• Regulates "Waters of the State" including isolated wetlands not covered federally

Water Quality Standards:

• Basin Plan for Central Valley Region establishes water quality objectives
• TMDL requirements integrated into NPDES permits

2. STATE REGULATORY REQUIREMENTS

Construction Stormwater Permits:

• Required for projects disturbing ≥1 acre
• Linear projects: ≥1 acre and >0.25 acre/mile
• Must file Notice of Intent (NOI) electronically through SMARTS system

BMP Design Standards:

• California Stormwater Quality Association (CASQA) BMP Handbooks widely adopted
• CGP requires Risk Level determination and corresponding BMPs
• Numeric Action Levels (NALs) for turbidity and pH

Post-Construction Requirements:

• Phase II MS4 permits require post-construction standards
• Low Impact Development (LID) prioritized statewide
• Hydromodification management requirements in some areas

Professional Certifications:

• Qualified SWPPP Developer (QSD) required for Risk Level 2 & 3 projects
• Qualified SWPPP Practitioner (QSP) required for implementation
• Professional Engineer not always required but often preferred

3. COUNTY/LOCAL REGULATORY STRUCTURE

Kings County Specific Departments:

• Kings County Community Development Agency - Planning Division
• Kings County Public Works Department - handles drainage and flood control
• Kings County Environmental Health Services

Stormwater Management:

• Kings County is not a Phase I or II MS4 permittee
• County relies primarily on state CGP requirements
• No separate stormwater utility district

City vs County Requirements:

• City of Hanford has separate MS4 permit and requirements
• Smaller cities (Lemoore, Corcoran, Avenal) may have individual standards
• Unincorporated areas follow County standards

Specific Ordinances:

• Kings County Code Title 16 - Subdivisions
• Kings County Code Chapter 9.36 - Flood Damage Prevention
• Kings County Grading Ordinance (Chapter 17.52)
• Kings County Improvement Standards (Resolution 19-068)

4. UNIQUE LOCAL REQUIREMENTS

Freeboard Requirements:

• County requires 1 foot of freeboard above BFE (FEMA minimum)
• Agricultural areas may have different standards

Stormwater Calculations:

• Rational Method typically used for areas <640 acres
• Must use Kings County rainfall data
• 10-year storm for local drainage, 100-year for major systems

Software/Modeling:

• No specific software mandated
• HEC-RAS accepted for floodplain analysis
• Must follow County Improvement Standards

Local Design Standards:

• Kings County Improvement Standards (2019)
• Standard retention: 10-year storm event
• Agricultural drainage considerations unique to Central Valley

5. STATE-LOCAL INTERACTION

Permit Sequencing:

• State CGP coverage required before local grading permit
• Local grading permit required before building permits
• 401 Certification needed before federal permits

Joint Processes:

• No formal joint application process
• County reviews state SWPPP for local compliance
• Regional Board may defer to local standards if more stringent

Local vs State Requirements:

• County generally adopts state minimums
• Additional requirements for agricultural interface areas
• Dust control more stringent due to Valley Air District

6. TECHNICAL STANDARDS

Storm Event Analysis:

• State: Risk-based approach, 2-year through 100-year depending on risk level
• Local: 10-year for local drainage, 100-year for flood protection
• Agricultural areas may use 5-year design storm

Runoff Coefficients:

• County provides specific coefficients for local soil types
• Must consider high groundwater conditions
• Percolation testing often required

Detention/Retention:

• Pre vs post-development runoff matching required
• Retention preferred over detention due to groundwater recharge goals
• Agricultural return flows must be considered

Water Quality:

• State CGP requirements apply
• Central Valley Salinity Coalition requirements may apply
• Agricultural discharge limitations

7. KEY DOCUMENTS TO REFERENCE

State Documents:

• Construction General Permit Order 2009-0009-DWQ (as amended)
• Central Valley Basin Plan
• CASQA BMP Handbooks
• California Storm Water Best Management Practice Handbooks

Local Documents:

• Kings County Improvement Standards (2019)
• Kings County Code Title 16 & 17
• Kings County General Plan (2035)
• Kings County Multi-Hazard Mitigation Plan
• County Standard Details and Specifications

SURPRISING ELEMENTS FOR OUT-OF-STATE ENGINEERS

State Level:

1. SMARTS System - Mandatory electronic filing and tracking system
2. Risk-Based Approach - Three risk levels with different requirements
3. QSD/QSP Certification - Specific state certifications required beyond PE
4. Numeric Action Levels - Enforceable numeric standards for turbidity
5. Waters of the State - Broader jurisdiction than federal Clean Water Act

Local Level:

1. Agricultural Interface - Extensive requirements for agricultural drainage compatibility
2. Groundwater Considerations - High groundwater impacts design significantly
3. Limited MS4 Coverage - Rural county with minimal MS4 requirements
4. Dust Control Integration - Air quality requirements integrated with erosion control
5. Regional Salinity Issues - Salt management requirements unique to Central Valley

Critical Coordination Points:

• San Joaquin Valley Air Pollution Control District requirements
• Irrigation district coordination often required
• Agricultural preserve setbacks and drainage easements
• Williamson Act considerations for agricultural land

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: FEMA NFHL (public MapServer)
• Precipitation Data: NOAA Atlas 14 Precipitation Frequency Data Server
• Analysis Date: 2025-09-08 13:29:19

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