| (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.
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