1 Groundwater David S. Rhodes Acquisition Integrated Project Team Chair Environmental Management Los Alamos Field Office March 3, 2015

2 Regulatory Framework for Water  New Mexico Water Quality Control Commission (NMWQCC) establishes standards Uses U.S. Environmental Protection Agency (EPA) drinking water standards NM applies the EPA standard to any affected regional aquifer water  EPA Clean Water Act standards apply for surface waters  NM certifications apply to any surface water discharges instead of receiving waters

3 Groundwater and Surface Water  Interim Facility-Wide Groundwater Monitoring Plan Planning in coordination with NNSA M&O in response to NMED-HWB direction on frequencies, analytes (what we sample for), and locations/screens Sampling, packaging, and shipping groundwater samples to analytical laboratories and receiving results, reviewing, and publishing results in the Environmental Information Management System (EIMS) (Intellus – publically accessible database) Reporting results to NMED-HWB in Periodic Monitoring Reports (PMR)  Surface Water Protection Monitoring Planning and strategizing surface water compliance in accordance with the EPA-issued Individual Permit for Storm Water (IP) Collecting samples, packaging, and shipping samples to analytical laboratories and receiving results, reviewing, and publishing results Installation and maintenance of stormwater controls, comparison to background concentrations, and evaluation of alternatives  Hexavalent Chromium Plume in Mortandad Canyon Conducting plume control interim measures to prevent off-site migration Supporting NMED-HWB consideration of alternatives and NMED-HWB development of a draft Statement of Basis for a remedy Execution of the selected remedy (likely as a capital asset project)

4 Groundwater and Surface Water  RDX High Explosive Plume in Cañon de Valle Surface water corrective actions to address soil contaminant impacts Subsurface evaluation and studies include cross-hole pump testing and considerations of remedy alternatives and supporting NMED-HWB drafting of a Statement of basis for a remedy Execution of NMED-HWB directed remedy actions  Surface Water Boundary Protection Evaluation of watersheds for contaminant migration off-site and redistribution of stormwater sediment transport with the associated installation of appropriate stormwater controls (beyond requirements of IP for Stormwater)  Vadose Zone Gas or Moisture Monitoring Continuation of soil vapor extraction at MDA-L, pore-gas monitoring at MDA-C, and moisture monitoring at MDA-T  Wells and Boreholes Installation of wells and boreholes, maintenance of the equipment and pads, and plugging and abandoning unnecessary locations

5 IFGMP  Interim Facility-Wide Groundwater Monitoring Plan (IFGMP) Shared between EM and NNSA programs  Quarterly, semi-annual, and annual sampling programs periodic monitoring reports per year percent of samples are able to be collected (dry holes and springs) Three weeks to collect samples Six weeks for data return from analytical laboratories Pueblo data review requirements before posting Publically-accessible database (result of chromium settlement) Standard format PMRs (NMED rejected EIMS data submittal only)  NMED frequencies are not data driven, but project groupings

6 Groundwater Monitoring Network  Extensive monitoring network More than 140 groundwater monitoring wells More than 200 monitoring points (screens) covering 3 zones More than 660 samples analyzed per year  Work-plan negotiated annually with NMED  Years of characterization and monitoring have come down to two main issues Chromium contamination RDX contamination

7 Groundwater contaminant plumes

8 Surface Water Controls Examples  Individual Permit for Stormwater (IP) IP issued in 2010, renewal in 2015? o Discharges from 405 SWMUs and AOCs o NM drinking water quality standard-based Target Action Levels (TAL) Stormwater samples at monitoring areas o Storm dependent – only half of sites flowed o Site/result screening process o Path to completion and removal from IP Installation of stormwater controls and confirmation sampling Alternative compliance pathways for anthropogenic and background contributors Semi-annual meetings with NMED and community interest organizations  Los Alamos/Pueblo Canyon Storm Water Quality Sampling System Early Notification System interface with Buckman Direct Diversion project

9 Surface Water Controls Examples  Extensive monitoring network  Watershed scale  Sample surface water at over 200 different locations  Monitoring to measure performance of mitigations Conducted in canyons Emphasis is on boundary stations Additional focus on potential post-fire effects

10 Surface water controls

11 Surface water controls

12 Hexavalent chromium Investigation  Monitoring well pump testing Extraction works in the center of the plume  Extraction pilot testing and plume boundary control Trying to bring plume edge to drinking water standard within 3 years  Geochemistry laboratory testing Whether natural attenuation can be a factor  Injection wells pilots Extraction water disposition pathway and shape plume  Corrective measures evaluation expected Fall 2016 to propose remedy

13 Chromium groundwater model

14 Chromium plume model

15 RDX contaminant plume  Surface water corrective measures implementation Potential springs treatment system o Permitting issues with natural system components Surface permeable reactive barriers (PRB) o September 2013 storms destroyed the PRB in canyon channel o Restoring is not cost-effective Significant removal done previously  Subsurface corrective measures evaluation Additional characterization wells Monitoring well pump testing Determination of potential remedies

16 Surface water boundary protection  Watershed scale stormwater controls Need to evaluate canyon performance Potential designs must address significant LANL traffic patterns (roadways)  Defense-in-depth Downstream of LANL Multi-Sector General Permit (MSGP) controls Downstream of IP controls and project cleanup activities Mitigates contaminant transport off-LANL property Protects Pueblo de San Ildefonso and Santa Fed County public drinking water supplies at the Buckman Direct Diversion Project in the Rio Grande

17 Vadose zone activities  MDA-T moisture monitoring Needed to input to Corrective Measures Evaluation (CME) o Mesa breathes; will moisture migrate downward?  MDA-L Soil Vapor Extraction To keep VOC plume from migrating further towards water table Works best under asphalt cap/roads/pads Previous pilot worked well, operating now Expect to see long-term benefits in reduction in VOC concentration levels Expect early indication of potential additional drum leakage  MDA-C pore-gas monitoring Minor plume Impacts adjacent NNSA facility construction

18 Groundwater wells and maintenance  Installation and replacement of additional wells, boreholes, and coreholes Typically ~5 wells of boreholes a year FY2015 has ~10 holes to be drilled  Maintenance of groundwater monitoring equipment, pads, and roads Well pumps fail and need replacement Wells pads and access roads have to be maintained to allow all-season access Reconfigure to develop, rehabilitate, rescreen, etc. as sample quality deteriorates