oregon greywater siting_presentation_05_13
TRANSCRIPT
Graywater and Groundwater: Site Tes2ng Considera2ons
Todd Jarvis, Ph.D. Cer2fied Engineering Geologist Cer2fied Water Rights Examiner
What others are saying.. Graywater puts an immense strain on leach fields , and helps to max out
your sep7c tank. Diver&ng your graywater into your landscape helps alleviate this problem and actually leads to less contamina&on of groundwater.
In fact, the ecosystem of a mulch basin around a plant makes for a very effec7ve wastewater treatment system…and wastewater is filtered more effec&vely when released on the surface of the ground rather than under.
The microbes in the soil convert organic impuri7es in the wastewater into nutrients, which are then available for uptake by the roots of the plants. The result is water that is purer than what is discharged from a sewage treatment plant.
“Graywater irriga2on systems save water and money”
-‐ Dave Walzer Santa Cruz Sen&nel interviewing Laura Allen of Graywater Ac&on-‐ 02/27/2010
What others are saying.. Contamina2on of surface water. If grey water does not percolate through
the soil, it can flow into creeks or other waterways untreated. Solu7on: discharge grey water underground or into a mulch-‐filled basin. Don't apply grey water to saturated soils. Apply grey water intermiHently so that it soaks in and soil can aerate between waterings. In general, contained grey water applica&on at least 50 feet from a creek or lake is not a problem.
Contamina2on of groundwater. It is all but impossible to contaminate groundwater with a grey water system. However, property owners with wells should not irrigate with grey water any closer to the well than county regula7ons allow for a sep7c tank leachfield.
Oasis Design aka Art Ludwig
Why do we need to heed what others are saying?
MIT Urban Planning Professor and conflict resolu7on expert Lawrence Susskind indicates that newspaper ar7cles and leHers to the editor are important in the discourse on resource planning because the United States is a representa7ve democracy where “...we can count on the media to help ci&zens educate themselves about the issues being deliberated by their elected representa&ves".
Journal of Water Resources Planning and Management editorial by former long7me World Bank consultant and Harvard Professor John Briscoe 7tled "The prac)ce and teaching of American water management in a changing world", Briscoe indicates that: "The new genera&on of partnerships must involve, inter alia:
“A focus on the real world, and thus an emphasis on partnerships (a) between prac&&oners-‐who-‐think, and researchers-‐who-‐understand-‐prac&ce...and (b) to engage with the progressive private sector which is likely to be the source of much innova&on in the water domain.”
State DHS Guidelines
Graywater is not listed as a “Poten2al Contaminant Source”
According to Tom PaUee of Groundwater Sec2on of DHS, unofficial concern about graywater rests with poten2al viral contaminants within the “Two-‐year Time of Travel Zones” in Public Water Supply Wells.
State DHS Guidelines Summary of Oregon's Suscep2bility (Sensi2vity) Analysis Procedures
Matrix Evalua2on
A series of matrices is used to evaluate the poten2al of [1] water migra2ng from the surface to the aquifer and [2] a given contaminant persis2ng and moving with the water. In each matrix, two parameters are ploUed. Their intersec2on within the matrix yields a score from 1 to 10. The higher the score, the greater the poten2al that these parameters will contribute to aquifer suscep2bility.
1. Traverse Poten2al.
2. Infiltra2on Poten2al.
3. Mobility Poten2al.
4. Leach Poten2al.
5. Suscep2bility.
State UIC Guidelines 340-‐044-‐0018 Authoriza2on of Underground Injec2on by Rule
Basic requirements for all storm water injec&on systems authorized by rule –
(E) The injec&on system is not located within the 2 year 2me-‐of-‐travel zone as delineated by the Oregon Health Division or closer than 500 feet to a public water supply well, whichever is more protec2ve.
(G) The injec&on system does not exceed a depth of 100 feet and does not discharge directly into groundwater or below the highest seasonal groundwater level.
(H) A confinement barrier or a natural or engineered filtra&on medium is present between the base of the injec2on system and the highest seasonal groundwater level and prevents contaminants from reaching groundwater, or the owner or operator implements best management prac2ces that prevent or treat storm water contamina2on before injec2on.
State On-‐Site Guidelines
• 340-‐071-‐0150 Site Evalua2on Procedures for On Site Sep2c Systems.
For the Site Evalua7on Report, the standards include, among other things "...applicants must provide at least two test pits, with dimensions and configura7on as directed by the agent, located approximately 75 feet apart and within the area of the proposed system, including the repair/replacement area", where "Soil profiles determined from test pits provided by applicant" and "Water table levels (as indicated by condi&ons associated with satura&on or water table observa&ons)".
Site tes&ng using On-‐site or UIC methods require holes which can serve as conduits for greywater to reach
groundwater without treatment
Unintended Consequences of using On-‐site or UIC si2ng standards -‐ “Guerilla Well-‐fare” or
Dueling Expert Situa2ons
From Jarvis (2010) Water Wars, War of the Well, and Guerilla Well-fare, Journal of Ground Water
Site Evalua2on and Permijng Situa2on “Invasive versus Self Evalua2on”
Oregon On-site or UIC standards applied to a graywater?
"Ludwig's Law"- "Experience with groundwater contamination from septics [and UIC] does not translate to greywater".
“OOSU corollary to Ludwig's Law” - "Experience with groundwater contamination from greywater does translate to septics".
Paul Stanton, Duckboy® Cards Inc.
Recommenda2on? The Shovel Test and Common Sense
The Conflict over Graywater “Green versus Black & White”
AWWA – White Paper on Graywater (2010)
"Graywater reuse is viewed by the green-leaning layperson as the panacea for water shortages, groundwater depletion, surface water contamination, and climate change"; and
"Graywater is seen by society's public health guardians (including the water utilities) as a threat to health and safety of the users themselves and their neighbors”.
"Neither of these caricatures of graywater is accurate, although an element of truth resides in each".
Portland State University Professor of Urban Studies and Planning Connie Ozawa suggests that any system developed for folding science and other sorts of information into decisionmaking must be able to make space for silent voices and multiple ways of knowing.
Mul2ple Ways of Knowing
Thank you for your aUen2on.