{"id":21167,"date":"2023-02-16T15:30:42","date_gmt":"2023-02-16T14:30:42","guid":{"rendered":"https:\/\/www.vtei.cz\/2023\/02\/vliv-vystavby-jezu-v-lokalite-abovce-slovensko-na-hladinu-podzemnich-vod-pripadova-studie-z-povodi-slane-2\/"},"modified":"2024-08-19T17:00:39","modified_gmt":"2024-08-19T16:00:39","slug":"impact-of-weir-construction-at-locality-abovce-slovakia-on-groundwater-levels-a-case-study-from-slana-river-basin","status":"publish","type":"post","link":"https:\/\/www.vtei.cz\/en\/2023\/02\/impact-of-weir-construction-at-locality-abovce-slovakia-on-groundwater-levels-a-case-study-from-slana-river-basin\/","title":{"rendered":"Impact of weir construction at locality Abovce (Slovakia) on groundwater levels \u2013 a case study from Slan\u00e1 river basin"},"content":{"rendered":"

ABSTRACT<\/h2>\n

The\u00a0construction of\u00a0weirs on\u00a0rivers affects the\u00a0dynamics of\u00a0groundwater levels. The\u00a0weir built on\u00a0the\u00a0river Slan\u00e1 in\u00a0the\u00a0year 2010 between the\u00a0village of\u00a0Abovce and Chanava brought the\u00a0opportunity to\u00a0study such impact due to\u00a0preexisting groundwater monitoring wells of\u00a0the\u00a0Slovak Hydrometeorological Institute. to\u00a0verify the\u00a0impact of\u00a0the\u00a0constructed weir on\u00a0groundwater dynamics in\u00a0the\u00a0area, records of\u00a0weekly data were used ranging from 1986 to\u00a02018. In\u00a0addition, the\u00a0spatial range of\u00a0influenced areas was carried out using geographical information systems, and spatial interpolation techniques were used. The\u00a0results showed that immediately after the\u00a0construction of\u00a0the\u00a0weir, the\u00a0groundwater level rose significantly.<\/p>\n

INTRODUCTION<\/h2>\n

The\u00a0construction of\u00a0weirs and other works damming watercourses are common practice in\u00a0the\u00a0world due to\u00a0the\u00a0effectivity of\u00a0the\u00a0water hydroenergetic potential. In\u00a0the\u00a02000s\u00a0 have been built several small hydro powerplants practically in\u00a0all main Slovak river catchments (V\u00e1h, Slan\u00e1, Orava, Poprad, Nitra, Hron, Horn\u00e1d) [1]. The\u00a0motivation was to\u00a0change the\u00a0energetic mix of\u00a0the\u00a0Slovak republic from mostly carbon-based to\u00a0renewable sources [2]. However other environmental, as\u00a0well as\u00a0hydrological aspects of\u00a0the\u00a0proposed energetic solution, has not been sufficiently taken into account in\u00a0the\u00a0landscape planning phase [3]. This has been proved in\u00a0the\u00a0actualized strategic document of\u00a0the\u00a0Ministry of\u00a0the\u00a0environment of\u00a0the\u00a0Slovak republic by a\u00a0decreased number of\u00a0the\u00a0river profiles that could be potentially used for future river weirs [4].<\/p>\n

However, if\u00a0the\u00a0planning process of\u00a0the\u00a0future river weirs should be environmentally acceptable, it is\u00a0necessary to\u00a0base an authorization process on\u00a0the\u00a0scientific datasets and information that are publicly presented.<\/p>\n

The\u00a0paper deals with groundwater dynamics in\u00a0the\u00a0Slan\u00e1 river basin influenced by a\u00a0river weir constructed in\u00a02010 near Abovce (Southeast Slovakia). Since the\u00a0Slovak hydrometeorological institute has continuously recorded groundwater levels before and after the\u00a0weir construction by nine monitoring wells in\u00a0the\u00a0area, is\u00a0the\u00a0paper an exciting contribution allowing insights into groundwater dynamics influenced by weir construction.<\/p>\n

The\u00a0general objective of\u00a0this study was to\u00a0describe and quantify the\u00a0impact of\u00a0the\u00a0constructed weir, on\u00a0the\u00a0groundwater table by using directly measured data by groundwater monitoring wells. Specific sub-objectives are:<\/p>\n

1) to\u00a0estimate impact of\u00a0weir construction on\u00a0groundwater levels of\u00a0nearest monitoring wells,<\/p>\n

2) spatial influence of\u00a0the\u00a0weir construction on\u00a0groundwater levels in\u00a0the\u00a0quaternary groundwater body (GWB) of\u00a0the\u00a0Slan\u00e1 river (SK1001100P).<\/p>\n

MATERIALS AND METHODOLOGICAL APPROACH<\/h2>\n

This study was conducted in\u00a0the\u00a0river Slan\u00e1 watershed in\u00a0Slovakia. The\u00a0Slan\u00e1 river is\u00a0located in\u00a0the\u00a0southern part of\u00a0central Slovakia, its spring is\u00a0in\u00a0Stolick\u00e9 vrchy. Slan\u00e1 river is\u00a0a\u00a0mid-altitude river with a\u00a0rain-snow outflow regime. The\u00a0weir constructed in\u00a02010 on\u00a0the\u00a0river Slan\u00e1 is\u00a0located between the\u00a0villages of\u00a0Abovce and Chanava and 10 km south from the\u00a0city of\u00a0Torna\u013ea (Fig.\u00a01) in\u00a0the\u00a0river kilometer 4.7. The\u00a0created weir has a\u00a0maximum usable gradient of\u00a03.2 m. The\u00a0weir captures a\u00a0watershed of\u00a0an area of\u00a01,821 km2. The\u00a0purpose of\u00a0the\u00a0weir is\u00a0hydroenergetic with an installed power of\u00a00.5 MW.<\/p>\n

\"\"<\/a>Fig.\u00a01. Localization of\u00a0the\u00a0studied watershed and weir near Abovce village; the\u00a0Upper left figure depicts watershed localization within the\u00a0Slovak Republic<\/h6>\n

The\u00a0groundwater underlying the\u00a0weir belongs to\u00a0the\u00a0SK1001100P groundwater body (Fig.\u00a02). It is\u00a0characterized as\u00a0formation of\u00a0intergranular aquifer of\u00a0the\u00a0alluvial sediments of\u00a0the\u00a0Slan\u00e1 river and its tributaries. The\u00a0water body SK1001100P has an area of\u00a0140.24 km2. The\u00a0water collector is\u00a0formed mainly from alluvial and terrace gravel, sand gravel, sand, proluvial sediments, which are characterized by high flow rates [5]. The\u00a0geological composition of\u00a0the\u00a0groundwater body (GWB) mainly consists of\u00a0fluvial sediments with some other sediments far more upstream [6]. In\u00a0the\u00a0affected groundwater body, the\u00a0Slovak hydrometeorological institute operates a\u00a0state observation network from which we selected 9 monitoring wells for this study (Fig.\u00a02). These monitoring wells are listed in\u00a0Tab. 1.<\/p>\n

\"\"<\/a>Fig.\u00a02. Quaternary groundwater body (GWB) of\u00a0the\u00a0Slan\u00e1 river (SK1001100P); GWB consists of\u00a0fluvial sediments (88 %) and other unconsolidated sediments and rocks (7 %), chemical sediments (2 %) and aeolian sediments (3 %) [6]; measuring objects (wells) are marked with a\u00a0red dot and object number according to\u00a0the\u00a0Slovak hydrometeorological institute database<\/h6>\n
Tab.\u00a01. Localization of\u00a0the\u00a0monitoring wells (objects) used in\u00a0the\u00a0study\"\"<\/a><\/h5>\n

Dataset of\u00a0groundwater level altitude with weekly measurement were used and 5 time periods were evaluated. The\u00a0whole time period used in\u00a0the\u00a0study was from 1986 to\u00a02018 and contains 1,670 weekly records. Long term period before the\u00a0construction of\u00a0weir (1986\u20132009, 1,200 weekly records) in\u00a0the\u00a0study is\u00a0named as\u00a0\u201cBefore 2\u201d, the\u00a0shorter time period before weir construction (2002\u20132009, 417 weekly records) in\u00a0the\u00a0study is\u00a0named as\u00a0\u201cBefore 1\u201d, the\u00a0same time period after the\u00a0construction of\u00a0weir (2011\u20132018, 418 weekly records) in\u00a0the\u00a0study is\u00a0named as\u00a0\u201cAfter 1\u201d, and a\u00a0combination of\u00a0the\u00a0periods is\u00a0named \u201cBefore 1 + After\u00a01\u201d (2002\u20132018, 887 weekly records).<\/p>\n

The\u00a0data were organized into hydrological years (November to\u00a0October), not into calendar years. The\u00a0dataset was first tested on\u00a0normal distribution by Shapiro\u2013Wilk test [7], then the\u00a0time periods were compared. The\u00a0annual median data were tested on\u00a0presence and direction of\u00a0trends by Mann-Kendall test [8]. Data homogeneity was tested by Pettitt\u00b4s test [9], Standard normal homogeneity test (SNHT) [10] and Buishand\u00b4s test [11], with significance level of\u00a00.05 and confidence level of\u00a095 %.<\/p>\n

GIS spatial interpolation method SPLINE was used to\u00a0interpolate the\u00a0difference of\u00a0median values of\u00a0groundwater levels for the\u00a0time period for (1986\u20132009) and for (2011\u20132018) (Fig.\u00a05).<\/p>\n

RESULTS<\/h2>\n

Changes in\u00a0groundwater level after weir construction near the\u00a0Abovce weir<\/h3>\n

Detailed groundwater level changes have been studied on\u00a0two monitoring wells (2918 \u2013 Abovce, 917 \u2013 Chanava) nearest to\u00a0the\u00a0Abovce weir. However, since the\u00a0monitoring well 2918 \u2013 Abovce is\u00a0situated only 416 meters above the\u00a0incremented weir, we provide detailed statistics of\u00a0groundwater level at\u00a0this monitoring point in\u00a0Tab. 2.<\/p>\n

Tab. 2. Statistical characteristics of groundwater levels for measuring object 2918 \u2013 Abovce; values are in groundwater level elevation in meters above sea level [m a.s.l.]; period \u201cBefore 2\u201d represents the whole available monitoring period of groundwater level previous to weir construction, \u201cBefore 1\u201d represents 7 year long period previous to weir construction, as well as\u00a0\u201cAfter 1\u201d represents the\u00a0same long period after the\u00a0weir construction; \u201cBefore 1 + After 1\u201d represents a\u00a0period of\u00a07 years before and 7 years after the\u00a0weir construction\"\"<\/a><\/h5>\n

By applying median values and time-identical 7year intervals (\u201cBefore 1 + After 1\u201d), it is\u00a0evident an increase of\u00a0the\u00a0groundwater level up to\u00a01.08 m. A\u00a0significant increase has been recorded also in\u00a0maximum and minimum groundwater levels. Tab. 3 lists all evaluated objects and the\u00a0calculated difference between the\u00a0time periods \u201cBefore 1\u201d and \u201cAfter 1\u201d. It is\u00a0evident that the\u00a0construction of\u00a0the\u00a0weir impacted the\u00a0nearest monitoring wells by evaluation of\u00a0water level difference. Objects 2918 \u2013 Abovce and 917 \u2013 Chanava are the\u00a0most affected. Their distance from the\u00a0weir is\u00a0416 meters by the\u00a0object 2918 \u2013 Abovce and 3,036\u00a0meters by the\u00a0object 917 \u2013 Chanava.<\/p>\n

Tab. 3. Overview of difference in median, max, and min between time periods \u201cBefore 1\u201d (2002\u20132009) and \u201cAfter 1\u201d (2011\u20132018) for all measuring objects used in the study (depicted in\u00a0Fig.\u00a02); values are in\u00a0groundwater level difference in\u00a0meters\"\"<\/a><\/h5>\n

Fig.\u00a03 and 4 show all weekly average groundwater level data measured in\u00a0the\u00a0most affected objects. The\u00a0influence of\u00a0the\u00a0river weir on\u00a0water level is\u00a0evident at\u00a0both stations. The\u00a0red line in\u00a0Fig.\u00a03 and 4 depict the\u00a0dynamics of\u00a0the\u00a0water level increase in\u00a0the\u00a0year 2010 when weir construction was completed. It is\u00a0obvious that the\u00a0groundwater level rose immediately after weir construction and remained higher in\u00a0comparison to\u00a0the\u00a0reference period
\n1986\u20132009 in\u00a0both monitoring wells.<\/p>\n

\"\"<\/a>Fig. 3. Difference of the weekly records of the groundwater levels in the period \u201cBefore 2\u201d (period 1986\u20132009 before the construction of the weir) and \u201cAfter 1\u201d (period 2011\u20132018 after the construction of the weir) on the measuring object 2918 \u2013 Abovce (distance 416 m of the weir); the red dotted line depicts the increase of the groundwater level in 2010 when the\u00a0weir was accomplished; brown line at\u00a0155.3 m a.s.l. represents ground<\/h6>\n
\"\"<\/a>Fig. 4. Difference of the weekly records of the groundwater levels in the period \u201cBefore 2\u201d (period 1986\u20132009 before the construction of the weir) and \u201cAfter 1\u201d (period 2011\u20132018 after the construction of the weir) on the measuring object 917 \u2013 Chanava (distance 3,036 m of the weir); the red dotted line depicts the increase of the groundwater level in 2010 when the\u00a0weir was accomplished; brown line at\u00a0160.5 m a.s.l. represents ground<\/h6>\n

The\u00a0results of\u00a0groundwater level data subjected to\u00a0trend analysis are shown in\u00a0Tab. 4. At\u00a0the\u00a0time period \u201cBefore 1 + After 1\u201d, a\u00a0statistically significant upward trend is\u00a0evaluated at\u00a0objects 2918 \u2013 Abovce and 917 \u2013 Chanava. However, when the\u00a0time periods \u201cBefore 1 + After 1\u201d, were evaluated individually, a\u00a0statistically significant trend was not found.<\/p>\n

Tab.\u00a04. Overview of\u00a0Mann-Kendall trend test analysis results\"\"<\/a><\/h5>\n

Subsequently, in\u00a0the\u00a0case of\u00a0time period \u201cBefore 1 + After 1\u201d, data homogeneity test was also performed. Pettitt\u00b4s test, Standard normal homogeneity test (SNHT) and Buishand\u00b4s test were applied. All tests identified a\u00a0break point at\u00a0the\u00a0beginning of\u00a02010, when the\u00a0weir in\u00a0Abovce was put into operation (Tab. 5).<\/p>\n

Tab.\u00a05. Results of\u00a0homogeneity test\"\"<\/a><\/h5>\n

The\u00a0same image is\u00a0provided by the\u00a0graph with the\u00a0identified break point, as\u00a0a\u00a0result of\u00a0Pettitts test, Fig.\u00a05. The\u00a0change in\u00a0mean values of\u00a0groundwater level is\u00a0clearly visible, together with the\u00a0identified breakpoint.<\/p>\n

\"\"<\/a>Fig.\u00a05. Pettitt change point detection for groundwater elevation levels in\u00a0time period \u201cBefore 1 + After\u201d on\u00a0the\u00a0measuring object 2918 \u2013 Abovce and object 917 \u2013 Chanava<\/h6>\n

Spatial extent of\u00a0Abovce weir influence on\u00a0groundwater level in\u00a0quaternary groundwater body of\u00a0the\u00a0Slan\u00e1 river<\/h3>\n

Fig.\u00a06 clearly shows that the\u00a0highest difference in\u00a0groundwater elevation is\u00a0located right near the\u00a0constructed weir and by the\u00a0monitoring wells. Change in\u00a0groundwater levels in\u00a0quaternary water body vary from 0.21 m near Rumince monitoring well (2915) to\u00a01.3 m around the\u00a0constructed weir (monitoring well 2918 Abovce). A\u00a0relatively high increase in\u00a0groundwater levels was also observed on\u00a0monitoring well 917 Chanava at\u00a0a\u00a0distance of\u00a03,036 m from the\u00a0Abovce weir. From the\u00a0spatial point of\u00a0view, the\u00a0river weir of\u00a0Abovce increased groundwater levels up to\u00a01.3 m on\u00a0the\u00a0area of\u00a015.25 km2 and up to\u00a00.21 m to\u00a00.4 m on\u00a0the\u00a0area of\u00a038 km2. Thus, the\u00a0Abovce river weir influenced almost 26\u00a0% of\u00a0the\u00a0waterbody SK1001100P area (an increase of\u00a0groundwater levels more than 0.21 m). Groundwater levels increase more than 1.1 to\u00a01.3 m was recorded on\u00a011 % of\u00a0the\u00a0water body area.<\/p>\n

\"\"<\/a>Fig. 6. The difference of groundwater levels for time periods 1986\u20132009 (\u201cBefore 2\u201d \u2013 before the construction) and 2011\u20132018 (\u201cAfter 1\u201d \u2013 after the construction) in the quaternary waterbody of the Slan\u00e1 river<\/h6>\n

DISCUSSION AND CONLUSION<\/h2>\n

The\u00a0rise of\u00a0the\u00a0groundwater level was an expected consequence of\u00a0constructing a\u00a0weir on\u00a0the\u00a0Slan\u00e1 river. The\u00a0rate of\u00a0increase (up to\u00a01.3 m near constructed weir) of\u00a0the\u00a0groundwater level is\u00a0probably due to\u00a0the\u00a0geological conditions at\u00a0the\u00a0area, which is\u00a0formed mainly by Quaternary sediments as\u00a0stated in\u00a0[6].<\/p>\n

However, quaternary sediments are prone to\u00a0anthropogenic contamination and pollution [12]. Based on\u00a0the\u00a0results presented in\u00a0the\u00a0work, it is\u00a0evident that the\u00a0construction of\u00a0even a\u00a0relatively small weir has a\u00a0regionally significant impact on\u00a0the\u00a0groundwater level. It depends, of\u00a0course, on\u00a0the\u00a0configuration of\u00a0the\u00a0terrain, the\u00a0geological subsoil, and the\u00a0characteristics of\u00a0the\u00a0weir construction structure itself [13]. Nevertheless, in\u00a0the\u00a0context of\u00a0increasing drought risk in\u00a0the\u00a0studied area [14] increase in\u00a0the\u00a0groundwater levels due to\u00a0the\u00a0construction of\u00a0the\u00a0Abovce weir could be stated as\u00a0potentially beneficial for agriculture.<\/p>\n

On the other hand, we must not neglect the issue of potential groundwater pollution through industrial activity and agricultural fertilizers [15]. Also, the risk of leaching toxic substances from illegal and historically forgotten landfills can be a risk [12, 16, 17]. Historically, such substances were often buried in pits near farms or the vicinity of municipalities, and no evidence was kept [18]. This concern is valid, as the size of the area on which the groundwater level has increased by more than 1 meter is 15.25 km2 and includes the cadastral territory of four municipalities. By comparison areas of elevated groundwater level with the Ecological Information System load [19], there is only one potentially risky location in the most affected area registered as a former gas station. However, it is located in the C register, containing records of rehabilitated and reclaimed sites that do not pose any danger. Another danger is the increased level of underground water reaching deep approx. 1 m below the surface (near the villages of Chanava and Abovce), easily reachable by foot construction activities during which toxic substances can leach into groundwater [20]. There may also be a risk of groundwater contamination by oil products in accidents of construction machinery and technology [21]. The above aspects should local and regional authorities to take into account in the process of permitting new buildings activities. The\u00a0contribution showed not only the\u00a0significant influence of\u00a0the\u00a0construction of\u00a0the\u00a0river weir on\u00a0the\u00a0water level in\u00a0the\u00a0Quaternary groundwater body of\u00a0the\u00a0Slan\u00e1 River (SK1001100P), but also on\u00a0risks that should be addressed in\u00a0the\u00a0future.<\/p>\n

Acknowledgements<\/h3>\n

This research was funded by the\u00a0Scientific grant agency of\u00a0the\u00a0Ministry of\u00a0Education, Science, Research and Sport of\u00a0the\u00a0Slovak Republic and Agency for support research and development within projects\u00a0 VEGA No. 1\/0392\/22 \u201cZranite\u013enos\u0165 vybran\u00fdch pr\u00edrodne a\u00a0antropog\u00e9nne naru\u0161en\u00fdch ekosyst\u00e9mov vo vz\u0165ahu k prebiehaj\u00facej zmene kl\u00edmy (Vulnerability of\u00a0selected natural and anthropogenically disturbed ecosystems in\u00a0relation to\u00a0ongoing climate change)\u201d and APVV-21-0224\u00a0 \u201cDynamika biometeorologick\u00fdch a\u00a0ekohydrologick\u00fdch tokov vo vybran\u00fdch lesn\u00fdch ekosyst\u00e9moch ovplyvnen\u00fdch r\u00f4znymi disturban\u010dn\u00fdmi faktormi (Dynamics of\u00a0biometeorological and ecohydrological flows in\u00a0selected forest ecosystems affected by various disturbance factors)\u201d.<\/em><\/p>\n

The Czech version of this article was peer-reviewed, the English version was translated from\u00a0the Czech original by Environmental Translation Ltd.<\/p>\n","protected":false},"excerpt":{"rendered":"

The\u00a0construction of\u00a0weirs on\u00a0rivers affects the\u00a0dynamics of\u00a0groundwater levels. The\u00a0weir built on\u00a0the\u00a0river Slan\u00e1 in\u00a0the\u00a0year 2010 between the\u00a0village of\u00a0Abovce and Chanava brought the\u00a0opportunity to\u00a0study such impact due to\u00a0preexisting groundwater monitoring wells of\u00a0the\u00a0Slovak Hydrometeorological Institute. to\u00a0verify the\u00a0impact of\u00a0the\u00a0constructed weir on\u00a0groundwater dynamics in\u00a0the\u00a0area, records of\u00a0weekly data were used ranging from 1986 to\u00a02018. In\u00a0addition, the\u00a0spatial range of\u00a0influenced areas was carried out using geographical information systems, and spatial interpolation techniques were used. The\u00a0results showed that immediately after the\u00a0construction of\u00a0the\u00a0weir, the\u00a0groundwater level rose significantly.<\/p>\n","protected":false},"author":8,"featured_media":18100,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[86],"tags":[3205,279,3074,3073,3075],"coauthors":[2960,2961,2962],"class_list":["post-21167","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-hydraulics-hydrology-and-hydrogeology","tag-abovce","tag-gis","tag-groundwater-table","tag-weir","tag-weir-construction"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/21167","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/comments?post=21167"}],"version-history":[{"count":9,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/21167\/revisions"}],"predecessor-version":[{"id":32035,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/21167\/revisions\/32035"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media\/18100"}],"wp:attachment":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media?parent=21167"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/categories?post=21167"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/tags?post=21167"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/coauthors?post=21167"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}