SECTION 12.202. Surface Coal Mining and Reclamation Operations on Areas or Adjacent to Areas Including Alluvial Valley Floors in the Arid or Semiarid Areas West of the 100th Meridian

(a) Alluvial valley floor determination.

(1) Before applying for a permit to conduct, or before conducting surface coal mining and reclamation operations within a valley holding a stream or in a location where the adjacent area includes any stream in the arid or semiarid regions of the United States, the applicant shall either affirmatively demonstrate, based on available data, the presence of an alluvial valley floor, or submit to the Commission the results of a field investigation of the proposed permit area and adjacent area. The field investigations shall include sufficiently detailed geologic, hydrologic, land-use, soils, and vegetation studies on areas required to be investigated by the Commission, after consultation with the applicant, to enable the Commission to make an evaluation regarding the existence of the probable alluvial valley floor in the proposed permit area or adjacent area and to determine which areas, if any, require more detailed study in order to allow the Commission to make a final determination regarding the existence of an alluvial valley floor. Studies performed during the investigation by the applicant or subsequent studies as required of the applicant by the Commission, shall include an appropriate combination, adapted to site-specific conditions, of:

(A) mapping of unconsolidated stream-laid deposits holding streams including, but not limited to, geologic maps of unconsolidated deposits and stream-laid deposits, maps of stream delineation of surface watersheds and directions of shallow ground-water flows through and into the unconsolidated deposits, topography showing local and regional terrace levels, and topography of terraces, flood plains and channels showing surface drainage patterns;

(B) mapping of all lands included in the area in accordance with this paragraph and subject to agricultural activities, showing the area in which different types of agricultural lands, such as flood irrigated lands, pasture lands and undeveloped rangelands, exist, and accompanied by measurements of vegetation in terms of productivity and type;

(C) mapping of all lands that are currently or were historically flood irrigated, showing the location of each diversion structure, ditch, dam and related reservoir, irrigated land, and topography of those lands;

(D) documentation that areas identified in this paragraph are, or are not, subirrigated, based on ground-water monitoring data, representative water-quality soil-moisture measurements, and measurements of rooting depth, soil mottling, and water requirements of vegetation;

(E) documentation, based on representative sampling, that areas identified under this paragraph are, or are not, flood irrigable, based on streamflow, water quality, water yield, soil measurements, and topographic characteristics; and

(F) analysis of a series of aerial photographs, including color infrared imagery flown at a time of year to show any late summer and fall differences between upland and valley floor vegetative growth and of a scale adequate for reconnaissance identification of areas that may be alluvial valley floors.

(2) Based on the investigations conducted under paragraph (1) of this subsection, the Commission shall make a determination of the extent of any alluvial valley floors within the study area and whether any stream in the study area may be excluded from further consideration as lying within an alluvial valley floor. The Commission shall determine that an alluvial valley floor exists if it finds that:

(A) unconsolidated stream-laid deposits holding streams are present; and

(B) there is sufficient water to support agricultural activities as evidenced by:

(i) the existence of flood irrigation in the area in question or its historical use;

(ii) the capability of an area to be flood irrigated, based on stream-flow water yield, soils, water quality, and topography; or

(iii) subirrigation of the lands in question, derived from the ground-water system of the valley floor.

(b) Application contents for operations affecting designated alluvial valley floors.

(1) If land within the proposed permit area or adjacent area is identified as an alluvial valley floor and the proposed mining operation may affect an alluvial valley floor or waters that supply alluvial valley floors, the applicant shall submit a complete application for the proposed mining and reclamation operations, to be used by the Commission, together with other relevant information, including the information required by subsection (a) of this section, as a basis for approval or denial of the permit. The complete application shall include detailed surveys and baseline data required by the Commission for a determination of:

(A) the essential hydrologic functions of the alluvial valley floor which might be affected by the mining and reclamation process;

(B) the significance of the area to be affected to agricultural activities;

(C) whether the operation will cause, or presents an unacceptable risk of causing, material damage to the quantity or quality of surface or ground waters that supply the alluvial valley floor;

(D) the effectiveness of proposed reclamation with respect to requirements of the Act and this chapter (relating to Coal Mining Regulations); and

(E) specific environmental monitoring required to measure compliance with §§12.610-12.613 of this title (relating to Alluvial Valley Floors: Monitoring) during and after mining and reclamation operations.

(2) Information required under this subsection shall include, but not be limited to:

(A) geologic data, including geologic structure, surficial geologic maps, and geologic cross-sections;

(B) soils and vegetation data, including a detailed soil survey and chemical and physical analyses of soils, a vegetation map and narrative descriptions of quantitative and qualitative surveys, and land-use data, including an evaluation of crop yields;

(C) surveys and data required under this subsection for areas designated as alluvial valley floors because of their flood irrigation characteristics shall also include, at a minimum, surface hydrologic data, including streamflow runoff, sediment yield, and water-quality analyses describing seasonal variations over at least 1 full year, field geomorphic surveys and other geomorphic studies;

(D) surveys and data required under this subsection for areas designated as alluvial valley floors because of their subirrigation characteristics, shall also include, at a minimum, geohydrologic data including observation well establishment for purposes of water-level measurements, ground-water contour maps, testing to determine aquifer characteristics that affect waters supplying the alluvial valley floors, well and spring inventories, and water-quality analyses describing seasonal variations over at least 1 full year, and physical and chemical analysis of overburden to determine the effect of the proposed mining and reclamation operations on water quality and quantity;

(E) plans showing how the operation will avoid, during mining and reclamation, interruption, discontinuance or preclusion of farming on the alluvial valley floors unless the premining land use has been undeveloped rangeland which is not significant to farming and will not materially damage the quantity or quality of water in surface- and ground-water systems that supply alluvial valley floors;

(F) maps showing farms that could be affected by the mining and, if any farm includes an alluvial valley floor, statements of the type and quantity of agricultural activity performed on the alluvial valley floor and its relationship to the farm's total agricultural activity including an economic analysis; and

(G) such other data as the Commission may require.

(3) The information required by paragraph (1) of this subsection shall evaluate those factors which contribute to the collecting, storing, regulating and making natural flow of water available for agricultural activities on the alluvial valley floor and shall include, but not be limited to:

(A) factors contributing to the function of collecting water which include, but are not limited to:

(i) the amount and rate of runoff and a water balance analysis, with respect to rainfall, evapotranspiration, infiltration and ground-water recharge;

(ii) the relief, slope, and density of the network of drainage channels;

(iii) the infiltration, permeability, porosity and transmissivity of unconsolidated deposits of the valley floor that either constitute the aquifer associated with the stream or lie between the aquifer and the stream; and

(iv) other factors that affect the interchange of water between surface streams and ground-water systems, including the depth to ground water, the direction of ground-water flow, the extent to which the stream and associated alluvial ground-water aquifers provide recharge to, or are recharged by, bedrock aquifers;

(B) factors contributing to the function of storing water which include, but are not limited to:

(i) surface roughness, slope, and vegetation of the channel, floodplain, and low terraces that retard the flow of surface waters;

(ii) porosity, permeability, water-holding capacity, saturated thickness and volume of aquifers associated with streams, including alluvial aquifers, perched aquifers, and other water-bearing zones found beneath valley floors; and

(iii) moisture held in soils or the plant growth medium within the alluvial valley floor, and the physical and chemical properties of the subsoil that provide for sustained vegetation growth or cover during extended periods of low precipitation;

(C) factors contributing to the function of regulating the flow of water which include, but are not limited to:

(i) the geometry and physical character of the valley, expressed in terms of the longitudinal profile and slope of the valley and the channel, the sinuosity of the channel, the cross-section, slopes and proportions of the channels, flood plains and low terraces, the nature and stability of the stream banks and the vegetation established in the channels and along the stream banks and flood plains;

(ii) the nature of surface flows as shown by the frequency and duration of flows of representative magnitude including low flows and floods; and

(iii) the nature of interchange of water between streams, their associated alluvial aquifers and any bedrock aquifers as shown by the rate and amount of water supplied by the stream to associated alluvial and bedrock aquifers (i.e., recharge) and by the rates and amounts of water supplied by aquifers to the stream (i.e., baseflow); and

(D) factors which make water available and which include, but are not limited to, the presence of landforms, including floodplains and terraces, suitable for agricultural activities.

(c) Requirements for approval.

(1) No permit or permit revision application for surface coal mining and reclamation operations on lands located west of the one hundredth meridian west longitude, shall be approved by the Commission, unless the application demonstrates and the Commission finds in writing, on the basis of information set forth in the application that:

(A) the proposed operation would not interrupt, discontinue, or preclude farming on an alluvial valley floor, unless the premining land use has been undeveloped range land which is not significant to farming on the alluvial valley floor, or unless the area of an affected alluvial valley floor is small and provides, or may provide, negligible support for production of one or more farms; provided, however, this subparagraph does not apply to those lands which were identified in a reclamation plan approved by the state prior to August 3, 1977, for any surface coal mining and reclamation operation that, in the year preceding August 3, 1977:

(i) produced coal in commercial quantities and was located within or adjacent to alluvial valley floors; or

(ii) obtained specific permit approval by the Commission to conduct surface coal mining and reclamation operations within an alluvial valley floor;

(B) the proposed operations would not materially damage the quantity and quality of water in surface and underground water systems that supply those alluvial valley floors or portions of alluvial valley floors which are:

(i) included in subparagraph (A) of this paragraph; or

(ii) outside the permit area of an existing or proposed surface coal mining operation;

(C) the proposed operations would be conducted in accordance with §§12.610-12.613 of this title (relating to Special Permanent Program Performance Standards--Operations in Alluvial Valley Floors) and all other applicable requirements of the Act and this chapter (relating to Coal Mining Regulations); and

(D) any change in the land use of the lands covered by the proposed permit area from its premining use in or adjacent to alluvial valley floors will not interfere with or preclude the reestablishment of the essential hydrologic functions of the alluvial valley floor.

(2) The significance of the impact of the proposed operations on farming will be based on the relative importance of the vegetation and water of the developed grazed or hayed alluvial valley floor area to the farm's production, or any more stringent criteria established by the Commission as suitable for site-specific protection of agricultural activities in alluvial valley floors. The effect of the proposed operations on farming will be concluded to be significant if they would remove from production, over the life of the mine, a proportion of the farm's production that would decrease the expected annual income from agricultural activities normally conducted at the farm.

(3) Criteria for determining whether a surface coal mining operation will materially damage the quantity or quality of waters subject to subparagraphs (A) and (B) of this paragraph include, but are not limited to:

(A) potential increases in the concentration of total dissolved solids of waters supplied to an alluvial valley floor, as measured by specific conductance in millimhos, to levels above the threshold value at which crop yields decrease, as specified in Maas and Hoffman, Crop Salt Tolerance--Current Assessment, Table 1, A Salt Tolerance of Agricultural Crops, unless the applicant demonstrates compliance with subparagraph (B) of this paragraph.

(i) Salt tolerances for agricultural crops have been published by E.V. Maas and G.J. Hoffman, in a paper titled Crop Salt Tolerance--Current Assessment, contained in The Journal of The Irrigation and Drainage Division, American Society of Civil Engineers, pages 115 through 134, June, 1977. Table 1, giving threshold salinity values is presented on pages 122 through 125.

(ii) The Maas and Hoffman publication is on file and available for inspection at the Surface Mining and Reclamation Division Office, Railroad Commission of Texas, 1701 N. Congress Avenue, Austin, Texas 78711;

(B) potential increases in the concentration of total dissolved solids of waters supplied to an alluvial valley floor in excess of those specified by Maas and Hoffman shall not be allowed unless the applicant demonstrates, through testing related to the production of crops grown in the locality, that the proposed operations will not cause increases that will result in crop yield decreases;

(C) for types of vegetation not listed in Maas and Hoffman as specified by the Commission, based upon consideration of observed correlation between total dissolved solids concentrations in water and crop yield declines, taking into account the accuracy of the correlations;

(D) potential increases in the average depth to water-saturated zones (during the growing season) located within the root zone of the alluvial valley floor that would reduce the amount of subirrigation land compared to pre-mining conditions;

(E) potential decrease in surface flows that would reduce the amount of irrigable land compared to pre-mining conditions; and

(F) potential changes in the surface- or ground-water systems that reduce the area available to agriculture as a result of flooding or increased saturation of the root zone.

(4) For the purposes of this subsection, a farm is one or more land units on which agricultural activities are conducted. A farm is generally considered to be the combination of land units with acreage and boundaries in existence prior to August 3, 1977, or, if established after August 3, 1977, with those boundaries based on enhancement of the farm's agricultural productivity and not related to surface coal mining operations.

Source Note: The provisions of this §12.202 adopted to be effective April 7, 1997, 22 TexReg 3093; amended to be effective November 4, 1997, 22 TexReg 10640.