BACKGROUND OF THE INVENTION

The present invention relates to underground storage of water and more specifically to a system and method which directs water to underground storage zones having available storage capacity. Embodiments of the presently disclosed system and method further may be directed toward water storage in land where the land surface is utilized for other purposes, such as for agricultural use, commercial construction, recreation, or where the surface of the land has been restored, thereby making efficient use of the land by allowing the concurrent use of the surface and subsurface. Embodiments of the presently disclosed system and method further may be directed toward the installation of a system of piping for directing water into an underground storage zone without disturbing any activity, crops, improvements, fixtures, or restored surface features of the land surface overlying the underground storage zone. Embodiments of the presently disclosed system and method may also be directed toward the installation of a system for directing water into an underground storage zone where the surface or topography of the land overlying the underground storage zone is inaccessible for installation activities because of terrain and/or topography of the surface of the parcel.

In the face of growing demand for water and the statutory and regulatory framework which address groundwater sustainability, industries which rely on groundwater, especially agriculture, recognize the need to increase surface water imports and expand underground water storage capacity. Underground water storage reservoirs provide an alternative to storage of water in open reservoirs. Underground water storage reservoirs, i.e., aquifers, will have one or more porous and permeable layers. Porosity and permeability are the aquifer properties which, respectively, refer to the pore volume available for water storage and the hydraulic conductivity of the aquifer. For utilization for underground water storage, an underground zone must have available pore space and water must be able to flow through the zone to be recovered for utilization for irrigation or other use.

Groundwater recharge is a water management tool by which surplus surface water supplies are stored underground for later recovery during periods of reduced water supply. Recharge reduces or eliminates the need to construct costly surface reservoirs which are prone to excessive evaporation losses, particularly in arid climates in the Western United States. With heavy rain or snow fall, water must be released from surface reservoirs must be released to make room for inflow. Recharge has the added benefit of improving water quality by filtration through underlying sediments.

In general, if farmers and municipalities and quasi-municipalities, such as water districts, irrigation districts and water storage districts (collectively “water districts”) are able to conserve water and bank some of their allocation, they will be able to reclaim it later, either for their own use or for sale. In programs offered by some water districts, incentives are offered to private landowners to provide groundwater recharge facilities for banking surplus water for future extraction. These programs typically anticipate that water will be delivered to the private recharge facilities through district-owned distribution systems and that the water will be introduced into the underground reservoir by surface recharge basins. However, the water district may also store surface water for others within district-owned recharge facilities and the water district receive benefit for storing the groundwater.

The surface recharge basins are typically open, unfarmed, fallow land. Thus, land utilized for providing recharge to the aquifer is typically dedicated nearly exclusively for that purpose and other surface uses for the land inhibited or completely excluded.

As opposed to surface recharge basins, some recharge facilities introduce the water into the underground reservoir by piping systems. This type of system expedites introduction of the water into the aquifer and thereby reduces evaporation losses. However, depending upon the design of the water storage facility, the underground reservoir may still require the dedication of significant areas of real property. Moreover, such systems do not, without additional control mechanisms or structure, identify the particular zones or depth into which the water is introduced. Identifying the zones or depth into the water is introduced can be a significant issue if the underground water storage facility is beneath a land surface utilized for agricultural purposes because saturation of the root-zone can be detrimental to the health of a crop. Other surface uses may also be adversely impacted by the intrusion of stored groundwater into the near surface region, such as surface uses for recreation and residential and commercial development.

With the above factors in mind, it is desirable to develop additional underground storage for groundwater. It would also be beneficial to be able diminish water loss through evaporation, to determine where the water is going and how much storage capacity remains and, in some cases, to receive alarms when a particular aquifer is full and ground water is approaching the surface so that water may be directed to alternative water storage facilities. In addition, the incentives offered by the above-described programs typically credit the owner of the banking and recharge facility with a “banked water account credit” which is a percentage of the water banked in the facility. While the transferability and fungibility of these credits is evolving throughout the country with the development of sustainable groundwater policies, in general the credits are a valuable asset realized by owners of groundwater recharge facilities, and a method which facilitates obtaining such credits is desirable.

SUMMARY OF THE INVENTION

In contrast to other known underground water storage systems and methods of utilizing the same, embodiments of the present invention provide for the delivery and storage of water into an aquifer disposed in parcels of land but without significant disturbance of the land surface or the activities being conducted on the land surface. For example, the present method provides for the installation of water storage distribution piping without any significant disruption of the ground surface overlying the aquifer. The disclosed method thereby allows the underground water storage system to be installed where the land surface is actively being utilized for agricultural, recreational, residential, commercial purposes or other uses where the land surface has improvements or fixtures which preclude or discourage installation activities. The present method may also be utilized where the land surface overlying the aquifer is environmentally sensitive, has been environmentally restored, or where there are topographical features which limit the surface activity required to install a system of water distribution piping.

Embodiments of the present invention may utilize a piping system to deliver water from a remotely located water storage facility, such as those maintained by water storage districts and irrigation districts to embodiments of the disclosed system. In the case of water stored by or on behalf of a quasi-municipality, such as a water district, rights to stored water may be reclaimed, transferred, sold, etc. as groundwater recharge credits.

Embodiments of the present invention may also utilize water invasion control systems to detect moisture, groundwater invasion and/or monitor the moisture levels in different underground zones. These control systems may actively prevent the oversaturation of upper soil layers, such as rootzones and upper soil layers utilized for construction of structures or other facilities. The water invasion control systems may suspend water flow into the aquifer if water infiltration begins or if the moisture content in the near-surface zone approaches an undesirable threshold. Through the use of digital control means and actuated valves, the water flow may be redirected into other groundwater recharge zones or into surface containment facilities.

In addition, embodiments of the present invention may control the underground zones into which water is introduced and may maintain a record of the water volumes introduced into specific zones. Embodiments of the present invention may also, through the use of multiple moisture detectors, monitor the remaining storage capacity and provide an automated alert to the property owner, a water district, or others when the storage capacity reaches a designated level. Upon reaching the designated level, recharge water may be directed to an alternative storage facility as directed manually or automatically.

Embodiments of the present invention may further incorporate subsurface pumps which can remove water from a particular zone either for use or for redirecting to a different location in the aquifer or to a surface containment facility in the event the aquifer is at its storage limit.

The aquifer may have one or more layers, where each layer has a particular porosity for storing water and a particular permeability, which is the characteristic of the layer which allows water to flow through the interstices of the layer. Orientation of the aquifer layers is defined herein as the attitude of the layers, in three-dimensional space. The sedimentary rock layers in which aquifers are typically found obey the laws of superposition, original horizontality, and lateral continuity. The law of original horizontality predicts that the original orientation of essentially all rock strata was horizontal. For this reason, if rock strata is found with some orientation other than horizontal, a force has acted upon the rock strata to re-orient it (change it from its original state).

The below-ground piping systems of the present invention are configured to be in a complimentary disposition with respect to the orientation of the aquifer, or with those portions of the aquifer having the greatest porosity and permeability, whereby long sections of conduit are oriented in accord with the orientation of the desired aquifer strata. Thus, it is desirable to maximize the surface area of conduit with respect to the corresponding surface area of the desired strata of the aquifer strata, such that water is efficiently released uniformly within the lateral reach of the desired strata. Accomplishing this goal may utilize the pre-installation investigation discussed below.

Piping systems of the present invention may be installed utilizing directional drilling techniques which enable segments of discharge piping to be installed at nearly horizontal orientations, thereby greatly increasing the rate of water discharge to the subsurface aquifer. With these techniques, boreholes for the pipe segments of the piping system may be drilled by a drilling rig located offsite (i.e., not located on the land surface overlying the subsurface aquifer). The drilling unit will be capable of drilling angled boreholes such that the boreholes may be initiated from the remote location with the borehole being directed, at an angle, to penetrate the strata overlying the subsurface aquifer. These boreholes may turn upwardly at the opposite end such that the borehole penetrates the ground surface at the end opposite the drilling rig to form an “exit hole”. Once the boreholes are completed or partially completed, piping segments utilized in the piping system are directed into the boreholes by the drilling unit, with the piping segments installed in an end-to-end configuration, forming a continuous “string” of pipe in a particular borehole. The pipe string may be installed by feeding the pipe into the borehole at the drilling rig location and, optionally, pulling the pipe string from the “exit hole”.

The piping segments may comprise slots for release of the water into the surrounding ground surface. Alternatively, the piping segments may be perforated or otherwise slotted by tools inserted into the string of pipe by the drilling unit. Embodiments of the method may further include pre-installation investigation of the strata of the aquifer as well as the strata overlying the subsurface aquifer. This pre-installation investigation may include a review of geophysical well logs and/or well cuttings from any water wells or oil wells in the vicinity of the aquifer. The pre-installation investigation may also include the drilling of boreholes into the aquifer and strata adjacent to the aquifer. These pre-installation steps may provide important information regarding the orientation, structure and continuity of the strata, the presence of any faults or geologic unconformities, and the permeability and porosity of the strata. The pre-installation investigator thereby facilitates placement of the distribution piping at optimal locations with respect to the subsurface aquifer to maximize flow to the aquifer. The pre-installation investigation provides valuable information regarding the optimal placement of the distribution piping for maximizing flow into the subsurface aquifer and the best placement of the moisture detectors to detect offsite flow, invasive flow, or upward flow into a crop root-zone.

