Use the archive archive below to learn
more about news, impacts and issues regarding the possible redesignation of the LPRV
aquifer to sensitive aquifer status. Select a topic from the list below and then CLICK
Minutes: June 20, 2000
Minutes: June 23,
ECONOMIC IMPACT ANALYSIS
Draft Final Report, 06/20/01
Download Full Report (PDF)
Phase I Progress, 01/04/01
LPRV AQUIFER: PROACTIVE OR REACTIVE MANAGEMENT?
Aquifer Water Balance
Groundwater Use: 1950-2000
Pocatello Water Service Areas
TCE Plume Location
Underground Storage Tanks
Water Use Cycle
You can also
about the LPRV aquifer
in Aquifer Protection!
Some archive entries are
others are in PDF format.
LPRV AQUIFER: A SENSITIVE RESOURCE
The Lower Portneuf River Valley Aquifer
(LPRV) is a fast moving, fairly shallow aquifer with a limited amount of soil cover over
gravels. The aquifer has been described as vulnerable through the source water assessment process (see Hot Water Topics) in addition to many geological studies. Past practices have
included activities that have impaired and have the potential to impair the aquifer.
The gradual deterioration in water quality which has
been occurring over the last 15 to 30 years (see chloride trends
and nitrate trends)
and more recently (see TCE plume
underground tanks) provide ample evidence that the aquifer is being impacted by
pollution originating at or near the land surface. If the sources of these contaminants
(such as septic systems, storm water runoff and hazardous
materials/fuels) are not controlled, the rate of water quality degradation will likely
accelerate and/or other, serious pollution threats will develop that will have to be dealt
with through remediation.
The lower Portneuf Valley aquifer is vulnerable because
of several factors:
1) Varied urban, residential, industrial, and
agricultural land uses with the potential to contaminate the water supply occur directly
over the aquifer.
2) Water and contaminants originating at the surface
can move quickly to the water table because the aquifer has minimal natural protection
(thin soil cover, shallow water table, highly permeable Bonneville
gravels between the surface and water table). GO VISIT the hydrology section
of the Digital Atlas of Idaho 2000 to learn more about the Bonneville Flood.
3) Numerous artificial sources of recharge associated
with urban/residential land uses (drain wells, ditches, septic leach fields) accelerate
the movement of contaminants to the water table.
4) The highly permeable aquifer spreads contaminants
rapidly, making it difficult to clean up contamination once it has entered the aquifer.
In addition, the lower Portneuf Valley aquifer and its
immediate tributary aquifers comprise the effective sole drinking water source for Pocatello, Chubbuck, and northern Bannock County.
All of these factors also exist in the Rathdrum Prairie
aquifer, where for the past 20 years, proactive management approaches have been developed
to provide enhanced groundwater protection against contaminant threats related to urban,
residential, and commercial development. These management approaches were implemented
because the same kinds of trends in water quality that the lower Portneuf aquifer is
experiencing were documented in the Rathdrum aquifer and future water quality was
projected to degrade with continued development.
For these reasons, the agreements and management
methods that were developed and adopted by communities and jurisdictions on the Rathdrum
Prairie aquifer comprise a valuable template for other Idaho communities, such as ours,
considering enhanced ways to improve groundwater protection.
Through efforts of the Panhandle Health District, Idaho
Department of Environmental Quality,
the Environmental Protection Agency, and
state and congressional appropriations, the Rathdrum Prairie aquifer was designated in
1980 as a Special Resource Water under state Water Quality Standards and Wastewater
Treatment Standards. Through this designation, citizens and officials have worked to
develop and adopt an integrated protection program. Because of its status, the Rathdrum
Prairie aquifer became the only aquifer in Idaho to be classified in the Sensitive
Resource category when the state groundwater Quality Rule (GWQ Rule) was promulgated.
Under the GWQ Rule, by default all Idaho aquifers are
classified in the General Resource category.
Only through a petition to DEQ can an aquifer be reclassified from the General category
into the more stringent Sensitive Resource category or into the less strict Other Resource
category. In principal, the intent of recategorization is to achieve a level of protection
which is best suited to the identified beneficial uses which an aquifer is deemed to
provide. To achieve the Sensitive Resource designation,
for example, more strict numeric water quality standards (lower allowable concentration
limits) and / or narrative standards (water quality goals and protection intent) are
established, with which to maintain or improve existing water quality, using a combination
of best management methods and best available management practices.
The advantages to recategorization
to a Sensitive Resource as a means of achieving protection is that it enables a
jurisdiction or a collective to identify:
a) what type of groundwater protection is needed and
feasible for their site-specific hydrologic, economic, and resource management conditions;
b) cooperatively develop management tools to achieve
that level of protection; and
c) to implement and enforce those tools uniformly
across an agreed management area. for
Although a state-sanctioned mechanism such as Sensitive
Resource reclassification is not necessary to achieve protection, a less formal agreement
among local jurisdictions may make it more difficult to ensure both long-term and uniform
enforcement of the necessary protective regulations across the management area and beyond
changes in political leadership.
The principal drawbacks to recategorization are
economic and hence political. For example, it will cost more to control sewage impacts
from homes built outside city limits (by requiring connection to municipal sewer services
or installation of enhanced sewage
treatment systems, or requiring fuel storage facilities to build enhanced containment
systems (e.g. double-walled tanks, lined fuel containment structures). Although such
measures will provide long-term benefits by reducing future remediation costs for
groundwater contamination, assigning economic value to such future benefits is difficult.
Ultimately, the decision whether or not to adopt
stricter protective measures will be a community-wide responsibility,
wherein water managers, citizens, and political leaders will need to work together to
decide what action if any will be taken. In the lower Portneuf Valley, where limited
future water capacity and development planning needs are already focused on the
community's future water supply, tying aquifer protection to the Our Valley, Our Vision
buildout planning efforts is a logical step to ensure that all sectors of the community
will have a say in defining future needs and the means of achieving shared community
Currently, a number of conditions have
come together to assist Idaho communities in general, and this community in particular, to
achieve aquifer protection if they so decide. In order to answer the most pressing
questions from political leaders and representatives of local commerce and industry on the
economic implications of aquifer protection, a special legislative appropriation was
obtained by Representative Roger Chase to fund an Economic Impact Analysis (see archive at
left), of the projected costs and benefits of adopting enhanced protection measures
compared to not adopting such measures. The results of this study, the first phase of
which was completed in May, 2001, provide important information on which all sectors of
the community can base decisions as to how to proceed.
In addition, individuals are encouraged to participate
in monthly meetings of the Portneuf groundwater Forum, a technical and policy advisory
group, and to join our group - the Portneuf
Valley Groundwater Guardian committee.