Northern Nevada Water Planning Commission
Water Management Plan
Proposed Work Plan Priority Study
Literature Search and Analysis
to Identify Alternatives for
Management of Groundwater
Quality Impacted by High Density
Septic System Developments
Background: Nitrate
Nitrate-N MCL is 10 ppm
 Dose not bind with soils
 Is highly soluble & travels with
groundwater
 Little or no retardation or
degradation
 Conservative solute that tends to
accumulate in ground water

Background: Septic Systems

18,000+ septic systems in Washoe
County

Extensive work in Spanish Springs links
septic systems to ground water
contamination

Other areas exhibit similar potential
Background: Previous Studies






Verdi: 1935, 1951, & 1985 studies link septics
to ground water contamination
Lemmon Valley: nitrate increased from 4 to
13 mg/L over ten years
Golden Valley: “pervasive spreading” of
nitrate contamination in 10 yrs
Cold Springs: nitrate risen above MCL in
shallow groundwater over 10 years
Washoe Valley: septics the source of nitrate
contamination of shallow ground water
Spanish Springs: maximum of 82 mg/L
Background:
Presentation
Previous
OutlineStudies
RWPC Sponsored The Septic Nitrate Baseline Data and Risk
Assessment Study Phase 1: Prioritization of Study Areas and
Assessment of Data Needs
by Christian Kropf, 2007

Identify areas potentially affected by septic nitrate effluent

Investigate the potential risk of contamination in these
areas

Prioritize these areas for further study
Project Areas
Final Rankings
Report Conclusion
Data Gaps
What’s
Presentation
Being Done
Outline
Now?
Currently we are using septic to sewer conversion
as our main management/mitigation tool in
Spanish Springs.

Problems:

Cost to extend infrastructure to affected parcels without
external funding source

Cost to affected property owner can be significant

Mandate to mitigate groundwater nitrate without
enforcement to see it trough to completion
What Management/Mitigation
Presentation Outline
Measures have been Considered?

Septic to sewer conversion

Septic system management programs

Small flow systems

De-nitrifying septic systems

Leachate collection system to TMWRF

Leachate collection system to package plant

Composting toilets
What
Presentation
Now?
Outline

The Kropf report has identified that a septic nitrate
contamination problem exists and has identified areas
which are being, or may need to be mitigated

Washoe County DWR has moved forward with septic to
sewer conversion program in Spanish Springs at a
significant cost which is not likely to be sustainable for
future phases.

We need a study to evaluate the cost effectiveness of
potential alternatives which could be implemented locally to
manage/mitigate nitrate contamination from septics
Proposed
Evaluation
Presentation
Outline
1. Literature search to identify the following
methods:
•
•
•
•
•
Technologies
Practices
Management techniques
Regulatory frameworks
Funding and financing strategies, including:
i Cost of technology, practice, etc., O/M
ii Financing alternatives such as assessment
districts, development fees, grants and loans
Proposed Evaluation
2. Evaluate method impacts to:
•
Existing services (e.g., Water Reclamation
Facilities, interceptor capacity)
•
Septic owners
•
Development community
•
Community at large
•
Regulatory agencies, codes and regulations;
(grandfathered parcels “entitled” to septics)
Proposed
Evaluation
Presentation
Outline
Project deliverables would include:
•
•
•
•
•
A description of technologies with references
Impacts to property owners, community and
municipal services
Financing options
Case studies (specifically of measures that could be
implemented locally)
Cost Benefit Analysis of methods employed (as they
relate to current local conditions)
Request
for Qualifications
Presentation
Outline
•
Work Plan Priority
•
Included in budget
•
Staff Evaluation Team
•
Qualified firms for consideration would
need understanding of both local
conditions as well as national trends in
addressing septic related water quality
issues.
Presentation Outline
QUESTIONS?