2023-04-07_REVISION - M2001046

• Permit No: M2001046
• IBM Index Class Name: Revision
• Doc Date: 4/7/2023
• Doc Name: Adequacy Review Response
• From: Brannon Sand & Gravel
• To: DRMS
• Type & Sequence: TR2
• Email Name: ECS
• Email Name: MAC
• Media Type: D
• Archive: No

Nix Site Groundwater Contamination Potential
March 31, 2023
CROSS SECTION B-B'
B /it
NW SE
ELEV IN ELEV IN
FEET METERS
Geotech Geotech DWR Varra DWR
WE-05-0023 WE-96-0006 permit Companies permit
m R 2 m 01 m 185299 Pit 115 11202-F
east face
490
4875 _
1
4800 ' 1460
4775 � � _ .—sc4
__ �•, ,� -
4750 KptlKpu 1450
In this cross section and in C-C',-Geotech-signifies data from a geotechrncal boring or group of borings VERTICAL EXAGGERATION 15X
Beneath is posted the CGS unique identifying number for the boring(s),followed by the bong number(s)
Figure 2.Cross section perpendicular to the St.Wain Creek valley running south of the Nix Site(from
Keller and others,2019)
2. WATER QUALITY STANDARDS AND REGULATIONS
The controlling groundwater standards set by the Water Quality Control Commission
(WQCC) in 5 CCR 1002-41 (Regulation 41) are the interim narrative standards described in
paragraph 41.5(C)(6). These standards were developed and implemented to minimize the
degradation of existing ambient groundwater quality. The Statement of Basis and Purpose
for the original rulemaking,states: "The narrative standards prohibit the introduction of
non-natural chemicals where best available information indicates a potential threat to the
public health, safety or welfare."We believe that the best available information for the Nix
Site do not indicate a potential threat to the public health,safety, or welfare.
The Nix Site is located outside of the areas of groundwater to which the WQCC has assigned
use classifications and site-specific water quality standards.As the implementing agency
for administering the interim narrative standards in Regulation 41, DRMS may apply
reasonable permit conditions to ensure compliance with these standards.
The Colorado Mined Land Reclamation Board Rules and Regulations for the Extraction of
Construction Materials (Construction Materials Rules) states that: "...permit conditions shall
be established for each operation that may have a reasonable potential to adversely affect the
quality of a specified area that has not been classified by the WQCC. Such permit conditions
may be in the form of numeric protection levels,practice-based permit conditions, or both."It
is not clear which parameters DRMS believes that operations at the Nix Site have a
11reasonable potential" to introduce that will adversely impact water quality.
As per the memorandum of agreement (MCA) including the WQCC and DRMS regarding the
implementation of SB 89-181, DRMS submits an annual report detailing their
Ak DINATALE WATER CONSULTANTS 3