2023-05-08_HYDROLOGY - M2001046

• Permit No: M2001046
• IBM Index Class Name: Hydrology
• Doc Date: 5/8/2023
• Doc Name: Water Monitoring - Groundwater
• From: Brannan Sand and Gravel CO
• To: DRMS
• Email Name: ECS
• Email Name: MAC
• Media Type: D
• Archive: No

TABLE OF CONTENTS
1. BACKGROUND..................................................................................................... 3
Figure 1: Nix Mine Site and Vicinity ............................................................................. 3
2. BASELINE GROUNDWATER DATA..................................................................... 4
2.1 Baseline Groundwater Quality Data................................................................... 4
Figure 2: Map of Wells on Nix Site (following page)..................................................... 4
Table 1: Baseline Groundwater Quality Data................................................................ 6
Figure 3: Nix Groundwater Levels, Groundwater Flow, and Adjacent Mine Sites......... 7
2.2 Baseline Groundwater Quantity Data................................................................. 7
Figure 4: Groundwater Hydrographs............................................................................. 8
3. WATER QUALITY MONITORING......................................................................... 8
3.1 Introduction........................................................................................................ 8
3.2 Sampling Methodology....................................................................................... 9
3.2.1 Background Monitoring and Point of Compliance (POC) Locations.................... 9
Table 2: Groundwater Monitoring Stations..................................................................10
3.2.2 Monitoring Frequency.......................................................................................11
3.2.3 Monitoring Parameters......................................................................................12
Table 3: Baseline and Operational Water Quality Parameters....................................12
Table 4: Omitted Parameters from CDPHE Regulation 41, Tables 1-4.......................13
3.2.4 Sampling Protocol.............................................................................................13
3.3 Analytical Procedures: Comparison to State Water Quality Standards..............15
3.4 Water Quality Mitigation Plan............................................................................15
3.5 Annual Report...................................................................................................16
4. WATER LEVEL MONITORING PLAN..................................................................16
4.1 Monthly Monitoring
4.2 Criteria and Trigger Values ...............................................................................16
Attachment A: Field Sheets and Instrument Calibration Sheet.......................................18
Attachment B: Well Construction and Yield Estimate Reports........................................21
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