Introduction

 

The fractured or hard rock geology of Eastern Madera County requires water management policies and practices that differ from those in the Western County.  Rather than collecting in a large "pool" below the surface, the Eastern County's ground water flows through fractures or channels in the rock below the surface.  These fractures or channels may be located close to the surface or they may 1000' or more below.  They may be large enough to accommodate significant annual flows or small enough accommodate only a seasonal "trickle." 

 

The supply of water in these fractures is dependant on annual precipitation. Accordingly, flows through these channels and, therefore supply, can be expected to increase during rainy periods and diminish during dry seasons or droughts.  Plants and wells using water do not lower water levels in the same manner as in a valley aquifer. Rather, they interrupt or siphon off the flow of some portion of ground water as it flows through these fractures. 

 

            The purpose of this report is to recommend policies and practices that reflect the findings in the AB 303 study report entitled "Groundwater Conditions in the Oakhurst Basin" prepared by Kenneth D. Schmidt & Assoc. These specific recommendations address three fundamental issues revealed in the findings of the study.

 

A. Well Interference.  That is, the impact of wells sited on "upstream" fractures on those wells sited "downstream."

B. Recharge.  The ability of fractures to recover their capacity to produce after extended periods of pumping.

C. Water Quality.  This issue concerns water's constituents, which determine whether groundwater is unsafe or unpleasant to drink, without further treatment.

 

Recommendations arising from this study fall into two broad categories:

 

1. A consistent approach or methodology for studying groundwater conditions in the hard rock region of Eastern Madera County; and,
2. Specific recommendations that can be translated into policies and practices for managing groundwater in the Oakhurst Basin.

 

Recommended Approach to the Study of Groundwater Conditions in Hard Rock Areas.

 Identify developing regions in Eastern Madera County, such as the Oakhurst Basin, that are characterized by fractured or hard rock.  Candidates are Coarsegold, North Fork and Raymond.

1. Identify topographical sub-areas, if they exist, within these developing regions.  These sub-areas can be identified by elevation, geology, rates of precipitation and groundwater flows.  Examples of these sub-areas in the current study are: Miami Creek/Peterson Creek; Oakhurst Sub Area; and Sierra Lakes.
2. Characterize the geology of each Sub-Area
3. Identify groundwater flows in each Sub-Area and relate these flows to recharge rates and problems of well interference.
4. Document the relationship between precipitation/snow melt and recharge for each of these Sub-Areas.
5. Identify water quality problems and relate them to specific locations within each Sub-Area.

 

A consistent approach to the study of groundwater conditions in different regions of Eastern Madera County will, nevertheless, produce different results in each region studied.  However, a consistent approach will result in policies and practices that can be rationalized on the basis of selected basin's physical reality.  This, in turn, will produce more credible policies and practices that are politically acceptable. 

 

Recommended Policies and Practices in the Oakhurst Basin.

 

            Prior to the results of the current AB 303 study, there has been little, if any, systematically collected data about the Oakhurst Basin's groundwater supplies.  As a

consequence, the County's ability to manage the Basin's water use has been limited to attempts at regulating demand through the well permitting process.  Water use management has been indirect through rule-based or prescriptive land use management decisions reflected in the well permitting process.  However, the lack of water supply information has resulted in vague regulations, controlling the issuance of well permits, which leave too much room for interpretation.2  Consequently, there is inconsistency in the practice of issuing permits; and, there is little or no ability to assess the cumulative impact of well permitting practices or predict their impact on water use.

 

The information generated by the AB 303 study remedies this situation in three ways.  First, it provides information on the supply of groundwater in the Oakhurst Basin that has not been previously available.  Second, it demonstrates the use of methods for accumulating similar information, in the future.  Third and most important, it reveals the principal source of uncertainty surrounding the supply of groundwater in the Oakhurst Basin.  That uncertainty lies in the direct relationship between the supply of groundwater in hard rock fractures and annual precipitation; and, the impact of that relationship on recharge rates.

 

Understanding that variations in rates of precipitation are a major source of water supply uncertainty accomplishes two things.  First, it reveals the inadequacy of rule-based water use decisions.  Depending on weather conditions, application of the same rule will produce different results in different years.  There is no ability to predict the long-term or cumulative effect of these decisions. 

 

Second, the results of the AB 303 study point to an alternative that solves this problem.  These results create the opportunity, if not the obligation, for Madera County to control water use by actively managing water resources in the Oakhurst Basin.  Active management is defined as maintaining a reasonable balance between demand for and supply of groundwater.1  The goal of maintaining this balance shifts the mode of decision making away from prescription to decisions based on judgments made by those responsible for meeting the objective.  Rules become the parameters that structure or place limits on these decisions, rather than serve as the sole reason for them.

 

The ability to make quality decisions, balancing demand for and supply of groundwater, depends on the information available and the ability of the decision maker to analyze it.  Accordingly, the recommendations in this report fall into three categories.

 

1. Recommendations that give the County better control over the well permitting process. Specificity in these practices will lead to more consistency in their application; better information on water use; and, the ability to predict the impact of new wells on the water supply. (Demand Side Recommendations)2
2. Recommendations for projects enabling the County to manage water supply in the Oakhurst Basin. These recommendations reduce the uncertainty created by the dependence on precipitation for groundwater supplies.  Their implementation will give the County better control over the supply of groundwater in the Basin.  (Supply Side Recommendations)
3. A recommendation giving decision makers the ability to analyze the complex interaction between the demand for and supply of groundwater.  Its implementation will enhance the ability of decision makers and improve the quality of their decisions.  (Managing Supply and Demand)

 

Demand Side Recommendations.

 

1. Individual Domestic Wells.  A 24-hour pump test during a period when no recharge is occurring on the land surface should be required.   Time to 100% recovery shall also be measured.  Maximum time to recover should be set, in consultation with a Certified Hydrologist.  The category of "shared well" should be eliminated - a well shall be, either, part of a system covered by # 2 below or an individual domestic well.  Additionally, a minimum lot size requirement of five (5) acres for individual wells is strongly recommended.
2. Public Supply Wells.  15-30 day pump tests during a period when no recharge is occurring on the land surface should be required.  Additionally, pilot tests that isolate and test individual fractures for water quality are recommended.  The purpose of these tests is to provide the following:
   1. Obtain well-defined trends in the decline of pumping rates over time. A well-defined trend is one that allows projections of pumping rates for maximum periods of time.  The actual duration of the test will be determined by the quality of the data obtained.  These tests should be conducted by or under the supervision of a Certified Hydrologist.
   2. Determine recharge rates.
   3. Determine well spacing criteria that avoid well interference and reduction of recharge.
   4. Determine levels of chemical and radiological elements in the proposed system well.

 

1. Subdivision Wells.  For proposed subdivisions, a complete hydrologic evaluation by a Certified Hydrologist should be required.  This evaluation shall provide: appropriate hydrologic maps; an evaluation of groundwater occurrence; water level depths; direction of groundwater flows; recharge rates; discharge rates; evaluation of aquifer characteristics to determine optimum pumping rates; chemical characteristics of the water; reports of all test wells drilled, and a map indicating spacing of proposed wells.  The hydrologic evaluation should contain the following conclusions:
   1. The amount of groundwater available for the entire development over an extended period of time covering projected wet and dry years. 
   2. As the development progresses, periodic tests should be required to determine whether the projections, in a. above, are correct.
   3. The feasibility of the proposed method of obtaining water - e.g. individual or community wells.  If community wells are proposed, the recommendations in #2 above apply.
   4. The anticipated depths and yields of proposed wells.
   5. The chemical and radiological characteristics of the water in the proposed wells.
   6. The type of wells to be proposed.

 

 

Supply Side Recommendations.

 

1. Development of Storage Facilities.  Because the level of groundwater recharge is directly related to the level of precipitation, well levels fall during the dry season and droughts; and, water shortages occur.  To eliminate unpredictable fluctuations in the annual supply of water, the County should develop a system of storage facilities.  During wet periods, water would be removed and stored for release and distribution during dry periods.
2. Reuse of Effluent.  A program should be developed to capture, treat and reuse effluent, from the Oakhurst Waste Water Treatment Plant, for non-potable uses such as golf course and landscape irrigation.
3. Water Quality Studies.  The AB 303 study reveals the extent to which uranium is a water quality problem in the Oakhurst Basin.  Very little information exists about the causes of uranium in the Basin or its location.  While the removal of uranium from water, once it is pumped, is technically feasible, its disposal is expensive, logistically difficult, and politically sensitive.  A more feasible solution is to conduct studies whose results can be translated into regulations that avoid drilling in areas where uranium is likely to exist.  The recommended studies are those that:

•a.       Locate uranium deposits;

1.  
   1. Identify the geologic conditions in which uranium is likely to be found.

 

Managing Supply and Demand.

            The interaction between supply and demand for groundwater is complex. The key to managing this interaction is acknowledging that annual groundwater supplies are dependant on precipitation.1  To successfully manage groundwater in the Oakhurst Basin, the County needs a tool that:

 

1.  
   1. Recognizes the dependence of annual groundwater supplies on precipitation; and,
   2. Permits the manipulation of information that reflects what happens to precipitation once it reaches the ground or melts.

 

This tool must accomplish three things:

 

1. Reflect groundwater conditions at any given time.
2. Provide information that enables an assessment of the cumulative impact of existing groundwater policies and practices.
3. Enable the estimation/prediction of the impact of water use decisions on future water supplies.

 

Such a tool does not currently exist for use in the Oakhurst Basin.  However, the technology and the ability to create such a tool is available.  Therefore, it is strongly recommended that Madera County invest in the development of a Groundwater Management Model that will enable it to manage the interaction between the supply and demand for groundwater in the Oakhurst Basin.  An additional criterion for this model is that it must be usable for similar purposes in other regions of Eastern Madera County, as they are identified.

 

Below is a conceptual rendition of the model based on the findings of the current AB 303 study.  It is the baseline from which professional modelers and statisticians will work to create a fully developed working model that meets the above criteria.  This baseline consists of two parts: the variables that represent the information to be manipulated by the model; and, the algorithm that reflects the relationships between the variables.

 

Variables

 

 

Posted by Ed Bailey GRI, Broker Associate, Instructor on 08/23/2008 12:13 AM

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P = Annual Precipitation, including snowmelt

E = Evapotransporation.  Evapotransporation is the water used by trees and plants.

PW = Water that penetrates the ground and is pumped.

R' = Claimed Stream Flow.  The Oakhurst Basin is generally defined as the watershed that contributes to the Fresno River and its tributaries.  The California Dept. of Water Resources (DWR) has granted limited water rights to surface water in the Fresno River to certain individuals.  The total amount of water covered by these rights is not available for storage or pumping. 

R'' = "Free" Stream Flow.  R'' is the quantity of runoff remaining after meeting the obligations discussed under R' above.

R = Total Runoff or Stream Flow, ((R = (R'+R''))

 

Relationships Between Variables (Algorithms).

 

The algorithm that reflects the basic relationships between variables is:

 

P = E+PW+R1

 

That is to say, when precipitation (P) falls to the ground or snow melts, the resulting water is either used by plants and trees (E); penetrates the surface and is pumped (PW);or runs underground or over the surface into streams (R).

 

As managers of demand for and supply of groundwater, the County is interested in knowing the value of a sub-set of R, that is R''.  R'' represents precipitation that is not used by plants and trees (E); not pumped (PW); and, not committed as surface rights by DWR (R').  The algorithm reflecting what decision makers want to know is:

 

R''= P - (E+PW+R')

 

That is to say, decision makers want to know, after it rains or the snow melts, how much water is left over after:

•c.       Use by plants and trees (Evapotransporation),

•d.      Pumping from existing facilities, and

•e.       Meeting commitments to water rights on the Fresno River and its tributaries?

 

There is one refinement that should be made as the model is developed.  Not all water represented by the value of R'' necessarily ends up in the Fresno River or one of its tributaries, as assumed by the above algorithm.  Some of this water percolates into the ground and enters fractures that may or may not empty into the Fresno River or its tributaries.  The AB 303 study reveals that elevation makes a difference. Water in fractures at elevations above the rivers and streams discharges into the streams and there is little or no percolation; and, therefore, little or no recharge of the groundwater.  Water in fractures below the rivers and streams percolates into fractures and is available for recharge.  Eventually, the model will have to account for this distinction.

 

A CAVEAT.  A model is only as good as the data it analyzes.  In the implementation of this recommendation, particular attention must be paid to developing statistically sound methods of collecting data for this model.  Correspondingly, those who develop and maintain the model must give assurance that its operations are suitable for the data that is to be managed

 

Implementation of Recommendations.

 

The plan to implement these recommendations should address the following issues:

 

•1.      Rules & Regulations

•2.      Procedures

•3.      Responsibilities

•4.      Resources

•5.      Timeline (Schedule)

 

Rules & Regulations

 

            It is recommended that Madera County ordinances # 17.48.010 & 17.48.020 be phased out and replaced with new ordinances and regulations requiring the specific procedures set forth, above, in the section entitled Demand Side Recommendations and the report entitled, "Groundwater Conditions in the Oakhurst Basin" by Kenneth D. Schmidt & Assoc. 

 

Procedures.

 

            1.  Differing procedures for well permit applications for domestic use by individuals and those for sub divisions and community systems should be created.  In the former case, individuals may apply directly for and receive a permit, upon completion of a well test that meets the recommended criteria.  In the latter case, well permit applications should come through the county department responsible for overseeing the project that gives rise to the application.  When that permit is issued, it should be returned to that department to be processed with the balance of considerations for the proposed project. Attached, as Exhibit A, is a schematic mapping out this procedure.

 

            2.  Quality decisions depend on accurate information.  A program to determine the information necessary to support quality decision making should be created.  Two criteria for this information are:

 

•a.       Creation and maintenance of an accurate and current picture of groundwater supplies; and,

•b.      Extrapolation and prediction of water use decisions effects.

 

3.  A procedure to provide the appropriate results of all tests, conducted in connection with well permits, to those responsible for maintaining the Basin's groundwater database.

 

           

Responsibilities.

 

Seven new areas of responsibility are created by these recommendations.

 

•1.      Responsibility for overseeing the introduction of the changes proposed in this report.

•2.      Responsibility for developing and overseeing a water storage development program in the Oakhurst Basin.

•3.      Responsibility for overseeing the water quality studies recommended above

•4.      Responsibility for decisions maintaining a balance between demand for and supply of water; including decisions to release water from storage facilities.

•5.      Responsibility for developing and maintaining a system to collect data and monitor groundwater conditions in the Oakhurst Basin.

•6.      Responsibility for the Groundwater Management Model. This consists of two parts:

•a.       Responsibility for overseeing the development of the model.

•b.      Responsibility for operating and maintaining the model.

•7.      It is recommended that a separate department be created with responsibility for managing the demand for and supply of water in Eastern Madera County.  This department should be under the jurisdiction of the Director, RMA.

 

Resources.

 

            The results of the AB 303 study create the opportunity for Madera County to treat groundwater in the Oakhurst Basin and, eventually, in the entire Eastern County as an independent resource.  As with any asset, financial resources must be provided for its protection and in order to realize its maximum value.  Accordingly, it is recommended that, within the organizational entity charged with the above responsibilities, financial resources be allocated to ensure these responsibilities are properly carried out. 

 

There are two types of costs associated with the implementation of this program: initial development or transition costs; and, operational costs.  Initial development costs include: model development, data base design, development of data collection procedures, creation of supply facilities, water quality studies recommended above, as well as other costs of transitioning from one system of management to another.  These are capital investments that can be funded by grant awards. The Proposition 50 Grant that has been awarded to Madera County, beginning in January 2006, provides funds that can be used for this purpose.  

 

Operational costs should be off set by fees charged to those who benefit from the reliability of water supplies provided by Madera County's management practices. 

 

To maintain proper control, the following operational budgetary accounts should be established, as a vehicle for overseeing the management of this resource:

 

•1.      Operation & Maintenance (O&M)

•2.      Reserve Accounts (RA)

•3.      Capital Improvement Projects (CIP)

•4.      Replacement Costs (RC)

•5.      Model Development Costs (MDC)

•6.      Database Management Cost (DMC)

•7.      Transition Costs (TC)

 

All of the above - i.e. Rules & Regulations, Procedures, Responsibilities and Resources - should be the direct responsibility of the department proposed above. and report to the Resource Management Agency (RMA) Director.  Exceptions are that County Counsel will have to participate in the creation and interpretation of the rules and regulations; and, the County Administrative Officer will have to participate in the creation of the budget items and management of the funds allocated to these activities.  However, it will be the responsibility of the department proposed above and the RMA Director to determine whether or not the rules and regulations are properly serving the County's ends - that is, properly supporting management of the relationship between demand for and supply of water.

 

Timeline for Implementation.

 

Implementation of these recommendations represents a significant change in the manner in which Madera County manages water in the Oakhurst Basin and, potentially, in the entire hard rock area of the Eastern County.  This implementation falls into two stages that are defined by the goal set by these recommendations: creating a reasonable balance between demand for and supply of groundwater.  The first stage is achieving that balance.  That is, determining the conditions that reflect a balance in demand and supply conditions.  This is necessary because those conditions do not currently exist.  The second stage is maintaining that balance, once it is achieved.

 

Accordingly, an Implementation Plan that evolves, in steps, over a 3-5 year period is necessary.  

 

 

Conclusions.

 

            This report began with the assertion that the conduct of the AB 303 study in the Oakhurst Basin was a model for conducting similar studies in other hard rock areas of Eastern Madera County.  The foregoing recommended policies and practices in the Oakhurst Basin also become a model for developing similar policies and practices in those regions.  It is recommended that a committee consisting of selected members of the Madera County Board of Supervisors, the Eastern Madera County Water Oversight Advisory Committee and the RMA Director be created to evaluate the impact of implementing these recommendations and their relevance to other portions of the Eastern County.

 

            Finally, it should be recognized that dependence of the Oakhurst Basin on groundwater makes its water supplies subject to the uncertainties of the weather.  These uncertainties can be further reduced by the introduction of surface water to the Oakhurst Basin and surrounding regions of Eastern Madera County.  The results of the AB 303 study should be treated as support for considerations, currently underway, to bring surface water to the Oakhurst Basin.  When combined with the recommendations in this report, a fully developed plan for surface water will give the County a clear picture of the most cost effective combination of water sources for the Eastern County.

      2 The specific regulations referred to here are Madera County codes 17.48.010 & .020.

1 The term "supply," as it is used here, is intended to refer to the quantity and quality of water.  It is assumed that water that is unsafe to drink falls outside the definition of supply.

2 These recommendations are summaries of those discussed in the AB 303 Report entitled, "Groundwater Conditions in the Oakhurst Basin."  See pp. 71-88 of that report  for the complete set of recommendations.

1 In this discussion, precipitation includes snowmelt.

1 This algorithm reflects the basic relationships found in a water budget   However, the term water budget, as conventionally used, does not address the complexity of groundwater studies in hard rock, in general, and the Oakhurst Basin, in particular.  The model proposed here goes beyond the complexity usually addressed in a water budget.