Water Reservoirs as an Element of Shaping Water Resources of Post-Mining Areas

Abstract

The aim of the study was to present the concepts of water reclamation and development of post-mining areas of the Adamów Lignite Mine following the termination of its excavating operation. The reclamation procedures will accelerate the process of restoring the devastated post-mining area to the natural environment and, above all, will contribute to the increase in local water resources. Several water reservoirs with different surface areas and capacities within the final excavations of opencasts were created. The reservoirs are used for water retention, recreation, melioration and flood control purposes, as well as for depositing overburden from other opencast excavations. In total, the construction of 5 water reservoirs will include 4 weirs, 7 monks and 3 culverts with damming as well as a number of kilometres of inflow and outflow channels. The schedule of works and expenditures of the investment amounts to PLN 14,509,512 and is divided into 5 stages, not only covering the construction of the reservoirs, but also the water and drainage infrastructure necessary for their proper operation. All constructed and planned water reservoirs (Przykona, Janiszew, Koźmin, Głowy, Adamów, Koźmin Końcowy and Władysławów) will become new permanent elements of the landscape and the hydrographic network, coupled with the catchment system of the Warta River. They will allow for an increase in the retention capacity of the Adamów Lignite Mine area from the previous 32.3 million m 3 to 219.6 million m 3 in the perspective of 2023. They will improve the microclimate of postmining areas and have a positive impact on the lands created as a result of reclamation. They will provide retention for the irrigation of adjacent agricultural areas and help reduce the economic and natural losses caused by flooding. They will open recreational opportunities for the residents of the surrounding areas, characterized by water shortages. The post-mining reservoirs, formed during mining operations, fit perfectly into the Small Retention Program. The existing and planned water bodies are the best proof confirming that the decisions taken in the field of reclamation for water purposes were right. As practice shows, the landscape shaping during the exploitation of lignite is a great opportunity for the post-mining region to create reservoirs in the places where they do not occur in nature.

The Use of Digital Terrain Models to Estimate the Pace of Filling the Pit of a Central European Granite Quarry with Water

“…(approximately 60 years (Table 2, Figure 5) with an average net supply of 138.5 m 3 •d −1 (Table 2, Figure 4A), only slightly higher than the average calculated supply (101.8 m 3 •d −1 (Table 2, Figure 4A) from the physiographic direct catchment) points to difficult hydrogeological conditions (which are confirmed in the geological documentation of the deposit [112]) and the fact that the quarry is supplied with rainwater from a direct catchment with a non-existent groundwater supply. Considering the cubic capacity of the pit (~5.1 million m 3 , potentially~3.34 million m 3 of retained water), this confirms the cases featuring the spontaneous filling of an open excavation pit with water over several years to several decades, as discussed in the literature [3,25,36,54,59,70,91,117]. For example, it is prognosed that the natural filling of the water reservoirs in the Bełchatów mine may take about 60 years, and if additional water is supplied from outside the depression bowl, it may take 18 years [71].…”

“…The prognosed retention capacity of the Strzelin I granite quarry (~3.3 million m 3 ), as well as the capacity of the potential Strzelin quarry lake that would emerge as a result of connecting the Strzelin I and II pits (~6.6 million m 3 ) [23], correspond with the capacity of the water reservoirs that emerged in mines of solid rock materials [42,53,60] or pit lakes created in the Adamów lignite mine (i.e., smaller reservoirs created in the area) [71,117]. It should be noted that a major part of the pit lakes presented in the literature refers to coal and lignite mines, and the capacity of water retained in such lakes reaches 30-60 million m 3 [20,89], quite often exceeding 100 million m 3 [20,41,57,91,117], even up to 330-350 million m 3 [55,61]. The prognosed capacity of the water reservoirs that are planned to be created in the lignite mine "Bełchatów" after discontinuation of its operations is expected to reach 1.3 and 1.7 billion m 3 , and in the "Turów" lignite mine, 1.2 billion m 3 [70,71].…”

“…In comparison to the pit lakes created in lignite mines, the quarry lake that will emerge in the Strzelin granite quarry will be decidedly smaller, but it will still be relatively large compared to other quarries (e.g., Zakrzówek, Tarnów Opolski, Świerki) [42,53,60]. In some open-cast mines, groundwater supply plays a significant role in filling the pit [41,58,117]. However, based on the geological documentation of the Strzelin deposit, no inflow of water to the drilling holes was found [112], as the water in the pit originated mainly from precipitation and surface runoff in the direct catchment of the pit [23].…”

“…It is estimated that, after the pillar separating the pits is eliminated, the target cubic capacity of the whole pit will reach approximately~11.6 million m 3 and may retain up to~6.6 million m 3 of water [23], which will potentially double the time required to fill the pit with water. Optionally, the pit may additionally be flooded with water from rivers (the literature presents such cases [3,31,36,50,59,71,117]) (e.g., from the Oława River). However, this possibility seems unlikely, as the pit is situated on the so-called Gallows Hill (the watershed between the catchments of the Oława andŚlęza Rivers [118]), which is situated 420 m from the riverbed and 10-20 m above the bed of the Oława River.…”

“…The role that flooded pits play in retention is particularly significant in areas with low water resources [12,[23][24][25][26], including Poland [124,125], and the use of closed down pits for water retention may increase the reservoir retention capacity of a catchment by several tens of times, especially in terms of small reservoir retention [23,117]. Additionally, closed mines and quarries may become an important element of the green [111,126] and blue infrastructure of urban areas [23,48], such as the InterContinental Shanghai Wonderland Hotel, located inside an old quarry, with a water reservoir, living walls on the quarry walls, green roofs in the hotel, and parks around the old quarry and hotel.…”