Suitability Evaluation of River Bank Filtration Along the Second Songhua River, China

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Article Suitability Evaluation of River Bank Filtration along the Second Songhua River, China

Lixue Wang, Xueyan Ye and Xinqiang Du * College of Environment and Resources, Jilin University, Changchun 130000, Jilin, China; [email protected] (L.W.); [email protected] (X.Y.) * Correspondence: [email protected]; Tel.: +86-130-2913-2161

Academic Editors: Y. Jun Xu, Guangxin Zhang and Hongyan Li Received: 17 February 2016; Accepted: 20 April 2016; Published: 30 April 2016

Abstract: The Second Songhua River is the biggest river system in Jilin Province, China. In recent years, the rapid economic development in this area has increased the prominence of water resources and water-related environmental problems; these include surface water pollution and the overexploitation of groundwater resources. Bank infiltration on the floodplains of the Second Songhua River is an important process of groundwater-surface water exchange under exploitation conditions. Understanding this process can help in the development of water resource management plans and strategies for the region. In this research, a multi-criteria evaluation index system was developed with which to evaluate the suitability of bank filtration along the Second Songhua River. The system was comprised of main suitability indexes for water quantity, water quality, the interaction intensity between surface water and groundwater, and the exploitation condition of groundwater resources. The index system was integrated into GIS (Geographic Information System) to complete the evaluation of the various indicators. According to the weighted sum of each index, the suitability of river bank filtration (RBF) in the study area was divided into five grades. Although the evaluation index system and evaluation method are applicable only to the Second Songhua River basin, the underlying principle and techniques it embodies can be applied elsewhere. For future generalization of the evaluation index system, the specific evaluation index and its scoring criteria should be modified appropriately based on local conditions.

Keywords: groundwater exploitation; river bank ﬁltration; Second Songhua River; water resources planning

1. Introduction With its rich and stable water quantity, good water quality, and easy access and management, river bank ﬁltration (RBF) is widely adopted in many countries and has become an important means of groundwater exploitation [1,2]. In Holland, Germany, Slovakia and Hungary, the proportion of total drinking water supplied by RBF water supply has reached 5%, 16%, 50% and 45%, respectively [3]. The northern regions of China have established a number of RBF waterworks since the early 1950s; these include the Songhua River waterworks in Heilongjiang Province, the Hunhe River waterworks in Liaoning Province, the Jiuwutan and Beijiao waterworks in Henan Province, and the Hanzhong waterworks in Shanxi Province [4]. To date, more than 300 large riverside RBF waterworks [5–8] have been established in China. The combined use of surface water and groundwater resources can be realized through RBF, which can stimulate and increase the recharge of river water to the aquifer [9]. However, the unreasonable exploitation of groundwater resources will lead to a continually descending groundwater level, the disruption of the hydraulic connection between groundwater and surface water, saltwater intrusion and land subsidence [10]. From the perspective of the surface water inﬁltration process and runoff

Water 2016, 8, 176; doi:10.3390/w8050176 www.mdpi.com/journal/water Water 2016, 8, 176 2 of 24 infiltration process and runoff variation along the river, Qin (1995) proposed a vertical seepage method by combining Manning’s Formula and Darcy’s law to calculate the water recharge capacity of riverWater water2016, 8, [11]. 176 The riverbed clogging issue was thought to be an important factor that affects2 of 24 the performance of the riverbank filtration system [12]. Han (1996), according to the landform unit of differentvariation RBF along waterworks, the river, Qindivided (1995) water proposed sources a vertical into four seepage types, method including by combining intermountain Manning’s valley, intermountainFormula and basin, Darcy’s alluvial-prolu law to calculatevial thefan water and coastal recharge plain capacity [4]; ofthe river researchers water [11 ].concluded The riverbed that the infiltrationclogging capacity issue was calculation thought to of be surface an important water factoris the key that link affects during the performance the water resources of the riverbank evaluation of RBFfiltration waterworks. system [12 Grischek]. Han (1996), and accordingRay (2009) to thepres landformented the unit surface-groundwater of different RBF waterworks, interaction divided issues at variouswater sourcesgeomorphologic into four types, settings, including from intermountain the headwate valley,rs of a intermountain river to its confluence basin, alluvial-proluvial with oceans/lakes [13].fan and coastal plain [4]; the researchers concluded that the infiltration capacity calculation of surface waterThe quality is the key of surface link during water the can water be resourcesimproved evaluation by the physical, of RBF waterworks.chemical and Grischek biological and processes Ray that (2009)take place presented in RBF the surface-groundwaterprocess. As surface interaction water infiltrates issues at variousgroundwater, geomorphologic the total settings, organic from carbon, the headwaters of a river to its confluence with oceans/lakes [13]. turbidity, heavy metals, inorganic substances, viruses, parasites and some microorganisms in surface The quality of surface water can be improved by the physical, chemical and biological processes water can be effectively reduced. In RBF systems, 60% of the total organic carbon and 90% of the that take place in RBF process. As surface water infiltrates groundwater, the total organic carbon, turbidityturbidity, can heavybe removed metals, [3,14]. inorganic Likewise, substances, 90% viruses, of chromium parasites and and arsenic, some microorganisms and 50% of cadmium, in surface zinc, lead,water copper can and be effectively nickel can reduced. be removed In RBF [15]. systems, The removal 60% of theof ammonia total organic nitrogen carbon can and reach 90% of 95% the [16], and turbiditythe removal can beof removedbacteria, [ 3parasites,,14]. Likewise, and 90%viruses of chromium can reach and 100% arsenic, [14]. and 50% of cadmium, zinc, lead,In the copper past, anda large nickel number can be of removed studies [ 15have]. The been removal conducted of ammonia mainly nitrogen for specific can reach RBF 95%waterworks. [16], Differentand the methods removal were of bacteria, developed parasites, to analyze and viruses the feasibility can reach 100%of RBF [14 systems]. [17–19]. For the feasibility research Inof theRBF past, sites a large in a numberregional of setting, studies Sandhu have been et conductedal. (2011) mainlyprovided for specificthe analysis RBF waterworks. results in India [14].Different So far, there methods are wereonly developedfew publications to analyze on the the feasibility suitability of RBFevaluation systems of [17 RBF–19]. on For the the scale feasibility of a river basin,research because of RBF a generalization sites in a regional of setting,site selection Sandhu criteriaet al. (2011) is very provided difficult. the analysis results in India [14]. So far, there are only few publications on the suitability evaluation of RBF on the scale of a river basin, In this research, the downstream river basin of the Second Songhua River was set as the study because a generalization of site selection criteria is very difficult. area and the potential suitable area for RBF was evaluated. Based on the analysis of regional natural In this research, the downstream river basin of the Second Songhua River was set as the study geographyarea and and the potentialhydrogeological suitable area conditions, for RBF was an evaluated. index system Based on was the analysisestablished of regional to evaluate natural the suitabilitygeography of RBF and along hydrogeological the main conditions,stem of the an river index in system the study was established area. to evaluate the suitability of RBF along the main stem of the river in the study area. 2. Study Area 2. Study Area The Second Songhua River is the largest river in Jilin Province, and originates from Tianchi Lake in the ChangbaiThe Second Mountains. Songhua RiverThe catchment is the largest area river is 7.3 in Jilin × 10 Province,4 km2, including and originates the tributaries from Tianchi of the Lake Yitong in the Changbai Mountains. The catchment area is 7.3 ˆ 104 km2, including the tributaries of the River, Yinma River, Mangniu River and others, and accounts for 38.2% of the total province area. The Yitong River, Yinma River, Mangniu River and others, and accounts for 38.2% of the total province study area focuses on the plain area of the Second Songhua River catchment with a total area of 2.46 area. The study area focuses on the plain area of the Second Songhua River catchment with a total area 4 2 × 10of km 2.46 (Figureˆ 104 km 1).2 (Figure1).

Figure 1. The Second Songhua River catchment. Figure 1. The Second Songhua River catchment.

Water 2016, 8, 176 3 of 24

Water The2016 , 8major, 176 cities in the study area include Changchun City, the provincial capital of 3 Jilinof 24 Province, and Jilin City, Dehui City, Jiutai City, Nong’an County, and Fuyu County. The total length of theTheWater Second 2016major, 8 ,Songhua 176cities in River the studyis approximately area include 330 Changchun km in the City,study thearea. provincial The Yinma capital River3 of is 24 Jilinthe largestProvince, tributary and Jilin of theCity, Second Dehui So City,nghua Jiutai River City, and Nong’an stems from County, Hulanling and Fuyu Mountain County. in ThePanshi total County, length of the Second Songhua River is approximately 330 km in the study area. The Yinma River is the Jilin Province,The major finally cities entering in the studythe Second area include Songhua Changchun River in City, Nong’an the provincial County. capital The Yitong of Jilin Province,River is the tributarylargestand tributary of Jilin the City, Yinma of Dehuithe RiverSecond City, and JiutaiSo nghuathe City, second River Nong’an tributar and County,stemsy of thefrom and Second Hulanling Fuyu County.Songhua Mountain The River. total in The lengthPanshi Yitong of County, the River stemsJilin Province,Second from the Songhua finally north Riverenteringof Qingding is approximately the SecondMountain Songhua 330 in kmYito inRiverng the County, studyin Nong’an area. Jilin The Province,County. Yinma The and River Yitong finally is the River flows largest is into the thetributary Secondtributary of theSonghua of Yinma the Second River. River Songhua andThe theav River eragesecond and annual tributar stems precipitation fromy of the Hulanling Second in Mountain Songhuathe study in River. Panshiarea Theis County, 400–700 Yitong Jilin Rivermm, decreasingstemsProvince, from fromthe finally north southeast enteringof Qingding to the northwest Second Mountain Songhua (Figure in Yito River2).ng Both inCounty, Nong’an sides Jilin of County. theProvince, Second The and Yitong Songhua finally River flowsRiver is the intoare tributary of the Yinma River and the second tributary of the Second Songhua River. The Yitong River dominatedthe Second bySonghua the valley River. plain The geomorphic average annual unit. Theprecipitation sedimentary in the plain study is dividedarea is into400–700 multiple mm, stems from the north of Qingding Mountain in Yitong County, Jilin Province, and finally flows into the blocksdecreasing between from rivers southeast with floodplain to northwest and terrace,(Figure and2). Boththe surface sides elevationof the Second decreases Songhua gradually River from are Second Songhua River. The average annual precipitation in the study area is 400–700 mm, decreasing thedominated southeast by to the the valley northwest plain (Figuregeomorphic 3). Quaterna unit. Thery sedimentsedimentary with plain good is permeabilitydivided into is multiple widely blocksfrom between southeast rivers to with northwest floodplain (Figure and2). Bothterrace, sides and of the surface Second Songhuaelevation River decreases are dominated gradually by from distributedthe valley in the plain Second geomorphic Songhua unit. River The Basin sedimentary with a thickness plain is divided of 10–30 into m. multiple The type blocks of groundwater between the southeast to the northwest (Figure 3). Quaternary sediment with good permeability is widely is mainlyrivers pore with groundwater floodplain and in terrace, the sandy and gravel the surface layer elevation and the decreasesgroundwater gradually table fromis shallow, the southeast generally distributed in the Second Songhua River Basin with a thickness of 10–30 m. The type of groundwater 1–3 mto below the northwest the ground (Figure surface.3). Quaternary The single sediment well groundwater with good permeabilityproduction rate is widely is generally distributed 1000–3000 in mis 3mainly/d. theSurface Second pore water groundwater Songhua and groundwater River in Basinthe sandy with are gravel a well thickness connected, layer of and 10–30 the and m. groundwater groundwater The type of table groundwater recharges is shallow, surface is mainly generally water in1–3 most mpore below areas groundwater the along ground the in river surface. the sandy(Figure The gravel 4).single layer well and groundwater the groundwater production table is shallow,rate is generally generally 1000–3000 1–3 m m3/d.below Surface the water ground and surface. groundwater The single are well well groundwater connected, production and groundwater rate is generally recharges 1000–3000 surface m3/d. water in mostSurface areas water along and the groundwater river (Figure are 4). well connected, and groundwater recharges surface water in most areas along the river (Figure4).

Figure 2. Rainfall isoline in the study area. Figure 2. Rainfall isoline in the study area. Figure 2. Rainfall isoline in the study area.

Figure 3. Surface topography of the study area. Figure 3. Surface topography of the study area.

Figure 3. Surface topography of the study area.

Water Water2016, 20168, 176, 8 , 176 4 of 244 of 24

Figure 4. Contour of the water table. Figure 4. Contour of the water table.

Municipal and industrial wastewater seriously affects the water quality of Second Songhua River. Municipal and industrial wastewater seriously affects the water quality of Second Songhua Annual emissions of wastewater in this basin are about 645 million tons, of which 44% arises in Jilin River. Annual emissions of wastewater in this basin are about 645 million tons, of which 44% arises Province. As total nitrogen, total phosphorus, ammonia nitrogen exceed the standard, water quality in Jilindeterioration Province. As in thetotal Yinma nitrogen, River total is very phosphorus, serious; the ammonia river length nitrogen in which exceed water qualitythe standard, is inferior water qualityto Gradedeterioration V water in quality the Yinma accounts River for 42.9%is very of theserious; total lengththe river [20 ].length Changchun in which City water is located quality in is inferiorthe to middle Grade reach V water of the quality Yitong accounts River, and for municipal 42.9% of and the industrialtotal length sewage [20]. hasChangchun had serious City impacts is located in theon middle water reach quality of of the the Yitong river [ 21River,]. The and Second munici Songhuapal and River industrial in Jilin sewage Province has has had abundant serious water impacts on waterresources, quality but of now the cannot river meet[21]. theThe needs Second of economic Songhua development, River in Jilin especially Province the waterhas abundant requirement water resources,of large but cities now [22]. cannot meet the needs of economic development, especially the water requirement of large cities [22]. 3. Methodology

3. Methodology3.1. Division of the Core Study Area of RBF In order to focus on the optimum area, the core study area of RBF was firstly separated considering 3.1. Division of the Core Study Area of RBF the following two criteria: In order to focus on the optimum area, the core study area of RBF was firstly separated 1. Natural geographical conditions. The plain area along the river was mainly considered as it is the considering the following two criteria: main place of production and human activity, which has a strong demand for water resources. 1. Natural2. Hydraulic geographical connection conditions. extent between The plain river area water along and the groundwater. river was mainly The feasibility considered of RBF as it is the mainis getting place worse of production and may even and be human impossible acti withvity, increasingwhich has distance a strong from demand river. In for order water resources.to get more complete background information on potential RBF sites, a large study area was 2. Hydraulicrecommended. connection According extent tobetween the runoff river quantity, water the and study groundwater. range of RBF The was dividedfeasibility along of theRBF is river (Table1). Where there is a surface water divide in the study range, this natural feature is getting worse and may even be impossible with increasing distance from river. In order to get used as the boundary of the study area. more complete background information on potential RBF sites, a large study area was recommended. According to the runoff quantity, the study range of RBF was divided along the river (TableTable 1.1).Core Where study there range is (distance a surface from water river) of divi riverde bank in the filtration study (RBF) range, along this river natural banks. feature is used as the boundary of the study area. Grade 1 2 3 4 5 Runoff (108 m3/a) ě600 600–250 250–100 100–40 <40 Table1. Core study range (distance from river) of river bank filtration (RBF) along river banks. Core study range (km) 20 18 15 13 10 Grade 1 2 3 4 5 TheRunoff scope of(10 the8 m study3/a) area of≥ RBF600 and the600–250 feasible region250–100 of RBF was determined100–40 by<40 overlay analysisCore of study areas thatrange satisfied (km) the above 20 two criteria, 18 such that any 15 areas that 13 did not satisfy 10 both criteria were excluded.

The scope of the study area of RBF and the feasible region of RBF was determined by overlay analysis of areas that satisfied the above two criteria, such that any areas that did not satisfy both criteria were excluded.

3.2. Suitability Evaluation Method of RBF

Water 2016, 8, 176 5 of 24

3.2. Suitability Evaluation Method of RBF

3.2.1. Evaluation Index System The aim of this research is to find potential suitable areas for future water development plans and further detailed investigation of RBF systems. The specific goal of RBF is mainly to provide sufficient water resources with good water quality. A multi-criteria RBF evaluation index system was established based on water quantity, water quality, the development and utilization conditions of groundwater resources and the interaction intensity between surface water and groundwater. The index weight and detailed scoring criterion were all based on specialist marking methods, which is more effective for a specific site but may not be applicable to other areas (Table2).

Table 2. RBF suitability evaluation index system.

Category of Evaluation Index Evaluation Index (X) Index Weight (W) hydraulic conductivity (K) 0.10 groundwater Water quantity aquifer thickness (M) 0.10 0.30 surface water runoff in cross-section (Q) 0.10 groundwater status of groundwater quality (G) 0.15 Water quality 0.30 surface water status of surface water quality (S) 0.15 groundwater hydraulic gradient (I) 0.05 possible inﬂuence zone width of 0.30 Interaction intensity between surface surface water under the condition of 0.15 water and groundwater groundwater exploitation (L) permeability of riverbed layer (R) 0.10 The exploitation condition of groundwater depth (D) 0.10 0.10 groundwater resource

The main reasons for index weight are explained as follows. (1) The sum of evaluation index weight is equal to 1 by value assignment. The index weight of water quantity, water quality and interaction intensity between surface water and groundwater each accounts for 0.3 of total weight individually, and this allotment reflected the aim and decisive factors of RBF suitability evaluation along the Second Songhua River. The index weight of development and utilization conditions of groundwater resources only account for 0.1 of total weight, because the factor will influence groundwater development cost and help to confirm the priority, but it is not a decisive factor for RBF suitability evaluation. (2) For the index of water quantity, the groundwater index accounts for 0.20 and surface water index accounts for 0.1, because the water source of RBF waterworks comes from riverside groundwater and surface water via bank filtration. Hydraulic conductivity and aquifer thickness influence the infiltration rate and capacity of surface water to aquifer. (3) For water quality, the index weight of groundwater and surface water are equal to 0.15. The groundwater quality only indicates the current status and treatment effect of RBF. In order to avoid any possible groundwater contamination from surface water, the treatment effect of RBF should not be addressed too much and the surface water quality should not be neglected. (4) The interaction intensity between surface water and groundwater controls the water exchange efficiency. Only those places within the influence zone of surface water, the aquifer prone to receiving sufficient water quantity through RBF, the permeability of riverbed layer controls the real water exchange rate and the groundwater hydraulic gradient partly reflects the real condition of aquifer property. (4) The index weight of groundwater depth accounts for 0.1, because it will only influence the priority order of potential RBF areas. Water 2016, 8, 176 6 of 24

3.2.2. Water Quantity

Hydraulic Conductivity (K) Aquifer hydraulic conductivity (K) reﬂects lithology and permeability of an aquifer. The scoring criterion of hydraulic conductivity is shown in Table3.

Table 3. Hydraulic conductivity (K) scoring criterion.

K (m/d) >100 100–50 50–20 20–5 5–1 1–0.1 <0.1 Index Value 100 90 80 70 60 30 0

Aquifer Thickness (M) A suitable RBF site requires a certain scale of aquifer for adequate water production. The aquifer thickness scoring criterion is shown in Table4.

Table 4. Aquifer thickness (M) scoring criterion.

M (m) >50 30–50 10–30 5–10 3–5 1–3 <1 Index Value 100 90 80 70 60 30 0

Runoff in Cross-Section (Q) The magnitude of runoff in a given cross-section of the landscape directly reﬂects the richness of the surface water quantity. The larger the annual average runoff, the greater the recharge potential of surface water to groundwater, and the greater the potential suitability of the area for RBF. The runoff in the cross-section scoring criterion is shown in Table5.

Table 5. Runoff in Cross Section (Q) Scoring Criterion.

Q (108 m3/a) 250–100 100–40 40–10 10–5 5–1 1–0.1 <0.1 Index Value 100 90 80 70 60 30 0

3.2.3. Water Quality Water quality status directly reﬂects whether surface water or groundwater is suitable for drinking, and indicates the degree of difﬁculty and cost of water treatment that will produce drinking water. In order to guarantee the water quality of potential waterworks, the water quality improvement effect of RBF was thought of as an additional assurance. According to China's Environmental quality standards for surface water (GB3838-2002) [23] and Quality standard for groundwater (GB/T 14848-93) [24] (see Appendix A), water of quality grades I, II and III can be used as drinking water directly. Water of quality grade IV must be treated before it is supplied for drinking. Because higher index values of the quality grade indicate lower quality water, the assigned index values decrease as water quality grades change from I to IV. Water of quality grade V is a negative factor for the suitability of RBF, and its index value is assigned a negative number. This can make the negative water quality factor play a decisive role in the process of suitability evaluation of RBF. The groundwater quality (G) and surface water quality (S) suitability scoring criterion is shown in Table6.

Table 6. Groundwater quality (G) and surface water quality (S) scoring criterion.

G/S I II III IV V and Worse than V Index Value 100 95 90 60 ´275 Water 2016, 8, 176 7 of 24

3.2.4. Interaction Intensity between Surface Water and Groundwater A large proportion of RBF waterworks primarily capture surface water; the interaction intensity between surface water and groundwater plays an essential role.

Hydraulic Gradient (I) under the Current Condition The hydraulic gradient directly reflects recharge-discharge relationship between surface water and groundwater, and it also indicates recharge-discharge conditions of the interaction zone. A positive hydraulic gradient was defined to represent scenarios in which river water recharges groundwater; similarly, a negative hydraulic gradient indicates that river water is recharged by groundwater. A positive value of hydraulic gradient is beneficial to RBF in most situations; however, a very large value for the hydraulic gradient might mean that riverside groundwater is being exploited intensively or that the interaction between surface water and groundwater is poor, because the very low permeability of aquifer or riverbed will obviously enlarge hydraulic gradient and decrease water exchange intensity. A negative hydraulic gradient indicates that the surface water cannot be induced into the ambient aquifer at present. Nevertheless, a negative gradient might be reversed and to be beneficial for RBF under groundwater exploitation condition. If the present negative hydraulic gradient is excessively small, it may indicate that the permeability of aquifer or riverbed is very poor, and the large groundwater recharge potential from river water should not be expected under any exploitation conditions. The hydraulic gradient suitability scoring criterion is shown in Table7.

Table 7. Hydraulic gradient (I) suitability evaluation criterion.

I (‰) >10 10–5 0–5 0 to ´5 ´10 to ´5 <´10 Index Value 40 80 100 90 80 60

Possible Influence Zone Width of Surface Water under the Condition of Groundwater Exploitation (L) The possible influence zone width by surface water indicates the range of the hydraulic connection between surface water and groundwater. The greater the hydraulic connection range between surface water and groundwater, the superior the RBF site. The possible influence zone width (L) was assumed to be equal to the ratio of the aquifer thickness (M) to the hydraulic gradient (I) in a specified cross section. The suitability scoring criterion for the possible influence zone width by surface water is shown in Table8.

Table 8. Scoring criterion for the possible inﬂuence zone width of surface water under the condition of groundwater exploitation (L).

M M M M L < M to to > M |I|max |I|max |I|average |I|average |I|min |I|min Inﬂuence Intensity Strong Medium Weak None Index Value 100 80 60 30

Permeability of Riverbed Layer (R) Riverbed permeability indicates the exchange capacity between surface water and groundwater. Riverbed permeability is calculated using the hydrogeological cross section of the riverbed obtained from a ﬁeld investigation as standard. Then, the lithology under the riverbed is analyzed to obtain its permeability, either by measurement or practical experience. The riverbed permeability suitability scoring criterion is shown in Table9. Water 2016, 8, 176 8 of 24

Table 9. Permeability of riverbed layer (R) suitability scoring criterion.

R (m/d) >5 1–5 0.5–1 0.1–0.5 0.05–0.1 0.01–0.05 <0.01 Index Value 100 90 80 70 60 30 0

The Exploitation Condition of the Groundwater Resource When considering the development and utilization of groundwater resources, groundwater depth is a primary concern because it indicates the cost of building RBF wells. If the groundwater depth is too far below the ground surface, it may be in a highlands area or in a cone of a groundwater depression. In those places, the extraction of groundwater requires more energy. The groundwater depth scoring criterion is shown in Table 10. Because groundwater depth is strongly inﬂuenced by regional characteristics, this standard should be adapted to different hydrogeology conditions.

Table 10. Groundwater depth (D) scoring criterion.

D (m) <5 5–10 10–15 15–20 20–25 25–30 >30 Index Value 100 90 80 70 60 30 15

3.2.5. Suitability Index According to the evaluation index system created above, the complex suitability index for a potential RBF site can be calculated by weighted summation using Equation (1).

A “ XK ˆ WK ` XM ˆ WM ` XQ ˆ WQ ` XG ˆ WG ` XS ˆ WS ` XI ˆ WI ` XL ˆ WL ` XR ˆ WR ` XD ˆ WD (1)

In Equation (1), A is the suitability index of a potential RBF site, X is the score of individual indices as defined in Tables3–10 and W is the weight of each corresponding index as defined in Table2. The RBF suitability was then classified into five grades according to the suitability index value (Table 11).

Table 11. RBF suitability grades.

Suitability Index Value Grade Suitability Evaluation 90–100 I Excellent suitable areas 80–89 II Good suitable areas 70–79 III Moderate suitable areas 60–69 IV Poor suitable areas <60 V Unsuitable areas

In areas for which RBF suitability grades are between I and III, water quality satisfies human drinking water requirements and does not need treatment, and water quantity is adequate. Furthermore, the exchange between river water and groundwater is intensive, the water quantity and water quality of RBF is guaranteed, and there are good development and utilization conditions of groundwater resources. In short, areas in grades I–III are suitable for RBF. In areas for which the RBF suitability grade is IV, either water quality does not satisfy drinking water requirements directly or the water recharge is insufficient. After water treatment and limited exploration, such areas may be suitable for limited-scale RBF waterworks. Areas in grade V are unsuitable for RBF works because of unacceptable water quality, high water treatment costs or insufficient water recharge to sustain extraction at the required rate and volume.

3.3. Spatial Analysis Based on GIS GIS (Geographic Information System) has many powerful functions such as data editing, data management, data conversion, projection transformation, geographic analysis, metadata management, Water 2016, 8, 176 9 of 24 spatial analysis, and overlay analysis [25]. Applying GIS to a regional suitability evaluation of potential RBF sites can improve the accuracy and efﬁciency of evaluation. Spatial analysis based on GIS was adopted to facilitate the evaluation of the various indicators.

4. Results and Discussion

4.1. The Core Study Area of RBF According to the terrain classiﬁcation standard, the altitude range of 0 m–200 m belongs to the plain area. The boundary of the right bank of the Second Songhua River is mainly determined by the surface water divide. The annual average runoff of the Yinma River is 9.44 ˆ 108 m3 (Dehui Hydrological Station) and it belongs to river grade V. The annual average runoff of the Yitong River is 3.7 ˆ 108 m3 (Nong’an Hydrological Station) and this river also belongs to river grade V. So, the part of Dehui City that is on the left bank of the Yinma River and Nong’an County on the left bank of the Yitong River should take a hydraulic connection between river water and groundwater as standard. Thus, using the Yitong River and Yinma River as the center, an area extending 10 km from both sides Waterof the 2016 rivers, 8, 176 was deﬁned as the core study area near the rivers (Figure5). 9 of 24

Figure 5. The core study area for evaluating RBF site suitability. Figure 5. The core study area for evaluating RBF site suitability.

4.2.4.2. Suitability Suitability Evaluation Evaluation for for RBF RBF Works Works 4.2.1. Water Quantity Suitability 4.2.1. Water Quantity Suitability The aquifer lithology of the Second Songhua River plain mainly is gravel and coarse sand, and The aquifer lithology of the Second Songhua River plain mainly is gravel and coarse sand, and the aquifer hydraulic conductivity is approximately 60 m/day. The aquifer lithology of the Yinma the aquifer hydraulic conductivity is approximately 60 m/day. The aquifer lithology of the Yinma River and the Yitong River plain is mainly medium sand and sandy clay, and the aquifer hydraulic River and the Yitong River plain is mainly medium sand and sandy clay, and the aquifer hydraulic conductivity is only 12.5 m/day. The distribution of aquifer hydraulic conductivity in the core study conductivity is only 12.5 m/day. The distribution of aquifer hydraulic conductivity in the core study area is shown in Figure6. area is shown in Figure 6. The aquifer thickness distribution in the core study area is shown in Figure7. In the area traversed by the Second Songhua River downstream of Jilin city and in the reach from the Yinma River estuary to Fuyu City upstream of the Second Songhua River, the aquifer thickness is usually 10 m–30 m, and as much as 50 m in some sections. In the area traversed by the Yinma River, the aquifer thickness of the middle reach from Jiutai to Dehui is 10 m–30 m, whereas the aquifer thickness of other regions is only 5 m–10 m. In the area traversed by the Yitong River, the aquifer thickness of the Changchun City reach and of the Nong’an County reach is relatively thin, but in other locations the thickness is 10 m–30 m.

Figure 6. Distribution of hydraulic conductivity.

The aquifer thickness distribution in the core study area is shown in Figure 7. In the area traversed by the Second Songhua River downstream of Jilin city and in the reach from the Yinma River estuary to Fuyu City upstream of the Second Songhua River, the aquifer thickness is usually 10 m–30 m, and as much as 50 m in some sections. In the area traversed by the Yinma River, the aquifer thickness of the middle reach from Jiutai to Dehui is 10 m–30 m, whereas the aquifer thickness of other regions is only 5 m–10 m. In the area traversed by the Yitong River, the aquifer thickness of the Changchun City reach and of the Nong’an County reach is relatively thin, but in other locations the thickness is 10 m–30 m.

Water 2016, 8, 176 9 of 24

Figure 5. The core study area for evaluating RBF site suitability.

4.2. Suitability Evaluation for RBF Works

4.2.1. Water Quantity Suitability The aquifer lithology of the Second Songhua River plain mainly is gravel and coarse sand, and the aquifer hydraulic conductivity is approximately 60 m/day. The aquifer lithology of the Yinma River and the Yitong River plain is mainly medium sand and sandy clay, and the aquifer hydraulic conductivity is only 12.5 m/day. The distribution of aquifer hydraulic conductivity in the core study area Wateris shown2016, 8 ,in 176 Figure 6. 10 of 24

Water 2016, 8, 176 Figure 6. Distribution of hydraulic conductivity. 10 of 24 Figure 6. Distribution of hydraulic conductivity.

Figure 7. Distribution of aquifer thickness. Figure 7. Distribution of aquifer thickness.

8 3 The runoffThe runoff of the of theSecond Second Songhua Songhua Rive Riverr is is very largelarge (approximately (approximately 150 150ˆ 10 × 10m8 /a).m3/a). The The runoff runoff of the Yinma River and the Yitong River is 9 ˆ 108 m3/a and 3 ˆ 108 m3/a, respectively. The annual of the Yinma River and the Yitong River is 9 × 108 m3/a and 3 × 108 m3/a, respectively. The annual average runoff of rivers in the study area is shown in Figure8. average runoff of rivers in the study area is shown in Figure 8. According to the distribution of aquifer hydraulic conductivity, aquifer thickness and runoff Accordingquantity in theto region,the distribution the water quantity of aquifer suitability hydraulic scores conductivity, assessed by using aqui Equationfer thickness (1) is shown and runoff in quantityFigure in9 the. The region, score distributionthe water quantity of all indexes suitabilit is showny scores in Appendix assessed B. by using Equation (1) is shown in Figure As9. The seen score in Figure distribution9, the suitability of all indexes of water is quantityshown in in Appendix most regions B. of the core study area is better than grade III. Only in the middle reach of the Second Songhua River and in the Songhua Lake upstream reach in Jilin City is the water quantity suitability relatively poor (grade IV). Overall, the suitability of water quantity in the study area is good and can basically ensure an adequate water supply for RBF wells.

Figure 8. Annual average runoff.

Water 2016, 8, 176 10 of 24

Figure 7. Distribution of aquifer thickness.

The runoff of the Second Songhua River is very large (approximately 150 × 108 m3/a). The runoff of the Yinma River and the Yitong River is 9 × 108 m3/a and 3 × 108 m3/a, respectively. The annual average runoff of rivers in the study area is shown in Figure 8. According to the distribution of aquifer hydraulic conductivity, aquifer thickness and runoff quantity in the region, the water quantity suitability scores assessed by using Equation (1) is shown in FigureWater 20169. The, 8, 176 score distribution of all indexes is shown in Appendix B. 11 of 24

Figure 8. Annual average runoff. Water 2016, 8, 176 Figure 8. Annual average runoff. 11 of 24

Figure 9. Distribution of water quantity suitability. Figure 9. Distribution of water quantity suitability. 4.2.2. Water Quality Suitability As seen in Figure 9, the suitability of water quantity in most regions of the core study area is better thanThe grade groundwater III. Only qualityin the middle assessment reach was of based the Second on the QualitySonghua standard River forand groundwater in the Songhua (GB/T Lake 14848-93) [24] using the monitoring results for chloride, ﬂuoride, sulfate, ammonia, total hardness, upstream reach in Jilin City is the water quantity suitability relatively poor (grade IV). Overall, the total iron, nitrite and nitrate as the evaluation index. The single-factor evaluation, which contrasts each suitability of water quantity in the study area is good and can basically ensure an adequate water water quality index to the national standard, was adopted to assess the water quality grade. The status supplyof for groundwater RBF wells. quality in the study area is shown in Figure 10. The surface water quality assessment was based on the Environmental quality standards for 4.2.2. surfaceWater Quality water (GB Suitability 3838-2002) [23] as a standard; the Water Quality Index was adopted for the Theassessment. groundwater The status quality of assessment surface water was quality based in on the the study Quality area standard is shown for in Figuregroundwater 11. Using (GB/T Equation (1), the scoring distributions of groundwater and surface water quality in the study area 14848-93) [24] using the monitoring results for chloride, fluoride, sulfate, ammonia, total hardness, were integrated to produce the water quality suitability distribution shown in Figure 12. total iron, nitrite and nitrate as the evaluation index. The single-factor evaluation, which contrasts each water quality index to the national standard, was adopted to assess the water quality grade. The status of groundwater quality in the study area is shown in Figure 10.

Figure 10. Groundwater quality status.

The surface water quality assessment was based on the Environmental quality standards for surface water (GB 3838-2002) [23] as a standard; the Water Quality Index was adopted for the assessment. The status of surface water quality in the study area is shown in Figure 11. Using Equation (1), the scoring distributions of groundwater and surface water quality in the study area were integrated to produce the water quality suitability distribution shown in Figure 12.

Water 2016, 8, 176 11 of 24

Figure 9. Distribution of water quantity suitability.

As seen in Figure 9, the suitability of water quantity in most regions of the core study area is better than grade III. Only in the middle reach of the Second Songhua River and in the Songhua Lake upstream reach in Jilin City is the water quantity suitability relatively poor (grade IV). Overall, the suitability of water quantity in the study area is good and can basically ensure an adequate water supply for RBF wells.

4.2.2. Water Quality Suitability The groundwater quality assessment was based on the Quality standard for groundwater (GB/T 14848-93) [24] using the monitoring results for chloride, fluoride, sulfate, ammonia, total hardness, total iron, nitrite and nitrate as the evaluation index. The single-factor evaluation, which contrasts each water quality index to the national standard, was adopted to assess the water quality grade. The

Waterstatus2016 of, groundwater8, 176 quality in the study area is shown in Figure 10. 12 of 24

Water 2016, 8, 176 Figure 10. 12 of 24 Figure 10. Groundwater quality status. Water 2016, 8, 176 12 of 24

Figure 11. Surface water quality status. FigureFigure 11. 11. SurfaceSurface water water quality quality status. status.

Figure 12. Distribution of water quality suitability in the core study area. Figure 12. Distribution of water quality suitability in the core study area. Figure 12. Distribution of water quality suitability in the core study area. AsAs seen seen in in Figure Figure 12, 12 ,water water quality quality is is distributed distributed across across the the core core study study in in discrete discrete areas. areas. In In the the FuyuFuyu AsCity City seen reach reach in Figure and inin 12, thethe water downstreamdownstream quality reach isreach distributed of of the the Yinma Yinma across River Riverthe estuary core estuary study of the of in Second thediscrete Second Songhua areas. Songhua In River, the River,Fuyuthe water theCity water qualityreach quality and suitability in su theitability downstream is grade is grade III. Other reach III. Other parts of the ofparts Yinma the of Second the River Second Songhua estuary Songhua Riverof the haveRiver Second grade have Songhua Igrade water IRiver, qualitywater thequality suitability. water suitability. quality In the su JiutaiInitability the City Jiutai is reach grade City of reachIII. the Other Yinmaof the parts Yinma River, of the theRiver, Second water the quality waterSonghua quality suitability River suitability have is grade grade is I, gradeI water I, butquality other suitability. parts of the In theYinma Jiutai River City are reach grade of theIII. InYinma the Yitong River, Riverthe water basin, quality the water suitability quality is suitabilitygrade I, but is othermainly parts grade of theIII and Yinma grade River V, distributedare grade III. sp Inoradically, the Yitong except River for basin, the Changchunthe water quality City reachsuitability where is themainly water grade quality III andsuitability grade V,is gradedistributed I. In general, sporadically, the water except quality for the suitability Changchun is of City an acceptablereach where standard the water in most quality of thesuitability study area. is grade I. In general, the water quality suitability is of an acceptable standard in most of the study area. 4.2.3. Interaction Intensity between Surface Water and Groundwater 4.2.3. Interaction Intensity between Surface Water and Groundwater The interaction intensity between surface water and groundwater was assessed using the river level The(H) interactionand the groundwater intensity between level (h) surface at 1 kmwater (L )and distant groundwater from the wasriver assessed bank to using calculate the river the hydrauliclevel (H) gradientand the groundwater(I = [(H – h)/L level]) at intervals(h) at 1 km along (L) thedistant river from of not the more river than bank 10 tokm. calculate The cross the sectionshydraulic at gradientwhich hydraulic (I = [(H –gradients h)/L]) at were intervals calculated along arethe shownriver of in not Figure more 13. than According 10 km. The to these cross calculations,sections at which the hydraulic hydraulic gradient gradients scoring were index calculated was assigned are shown and in distributed Figure 13. asAccording shown in to Figure these 14.calculations, the hydraulic gradient scoring index was assigned and distributed as shown in Figure 14.

Water 2016, 8, 176 13 of 24

but other parts of the Yinma River are grade III. In the Yitong River basin, the water quality suitability is mainly grade III and grade V, distributed sporadically, except for the Changchun City reach where the water quality suitability is grade I. In general, the water quality suitability is of an acceptable standard in most of the study area.

4.2.3. Interaction Intensity between Surface Water and Groundwater The interaction intensity between surface water and groundwater was assessed using the river level (H) and the groundwater level (h) at 1 km (L) distant from the river bank to calculate the hydraulic Water 2016gradient, 8, 176 (I = [(H – h)/L]) at intervals along the river of not more than 10 km. The cross sections13 at of 24 which hydraulic gradients were calculated are shown in Figure 13. According to these calculations, the Water 2016, 8, 176 13 of 24 hydraulic gradient scoring index was assigned and distributed as shown in Figure 14.

Figure 13. Cross sections for calculation of hydraulic gradients. Figure 13. Cross sections for calculation of hydraulic gradients. Figure 13. Cross sections for calculation of hydraulic gradients.

Figure 14. Distribution of hydraulic gradient. Figure 14. Distribution of hydraulic gradient. Then, using the calculated cross sections of the hydraulic gradient, the possible inﬂuence zone Figure 14. Distribution of hydraulic gradient. Then,widths using of surface the calculated water were cross determined sections and of assigned the hydraulic a score (fromgradient, Table the8), aspossible shown ininfluence Figure 15 zone. widths of surfaceThe locations water of were hydrogeology determined proﬁles and assigned based on a drilling score (from results Table are shown 8), as shown in Figure in 16Figure. For 15. Then, using the calculated cross sections of the hydraulic gradient, the possible influence zone each cross section, the lithology under the riverbed was analyzed and, using the Handbook of widths of surface water were determined and assigned a score (from Table 8), as shown in Figure 15. Hydrogeology [26] to obtain a value of the lithology permeability, the lithology permeability was

Figure 15. Distribution of the possible influence zone width of surface water. Figure 15. Distribution of the possible influence zone width of surface water.

Water 2016, 8, 176 13 of 24

Figure 13. Cross sections for calculation of hydraulic gradients.

Water 2016, 8, 176 14 of 24

multiplied by 0.1 to determine riverbed permeability. For example, Figure 17 shows the No. 3 hydrogeology proﬁle from Xinlitun to Shaokou; the lithology layer incised by the river is comprised of sand gravel and its hydraulicFigure conductivity14. Distribution (based of onhydraulic experience) gradient. is 50 m/day–100 m/day. In this assessment, the hydraulic conductivity of the sand and gravel (75 m/day) was adopted; thus, the Then,riverbed using permeability the calculated at this cross cross sectionsections was of 7.5 the m/day. hydraulic The distribution gradient, of riverbedthe possible permeability influence is zone widths ofshown surface in Figure water 18 were. According determined to the riverbed and assigned permeability a score suitability (from evaluation Table 8), criterion as shown (Table in9 Figure), 15. the riverbed permeability was assigned a score.

Water 2016, 8, 176 14 of 24

The locations of hydrogeology profiles based on drilling results are shown in Figure 16. For each cross section, the lithology under the riverbed was analyzed and, using the Handbook of Hydrogeology [26] to obtain a value of the lithology permeability, the lithology permeability was multiplied by 0.1 to determine riverbed permeability. For example, Figure 17 shows the No. 3 hydrogeology profile from Xinlitun to Shaokou; the lithology layer incised by the river is comprised of sand gravel and its hydraulic conductivity (based on experience) is 50 m/day–100 m/day. In this assessment, the hydraulic conductivity of the sand and gravel (75 m/day) was adopted; thus, the riverbed permeability at this cross section was 7.5 m/day. The distribution of riverbed permeability is shown in Figure 18. According to the riverbed permeability suitability evaluation criterion (Table

9), the riverbed permeabilityFigure 15. wasDistribution assigned of the a possiblescore. inﬂuence zone width of surface water. Figure 15. Distribution of the possible influence zone width of surface water.

Figure 16. Location of hydrogeology cross sections. Figure 16. Location of hydrogeology cross sections.

Figure 17. Illustration of the No. 3 hydrogeology profile.

Water 2016, 8, 176 14 of 24

Figure 16. Location of hydrogeology cross sections. Water 2016, 8, 176 15 of 24

Water 2016, 8, 176 15 of 24 Water 2016, 8, 176 15 of 24 Figure 17. Illustration of the No. 3 hydrogeology proﬁle. Figure 17. Illustration of the No. 3 hydrogeology profile.

Figure 18. Distribution of riverbed permeability. Figure 18. Distribution of riverbed permeability. Figure 18. Distribution of riverbed permeability. Using Equation (1), the distribution of scores for hydraulic gradient, possible interaction zone widthsUsingUsing of surface Equation Equation water, (1), (1), the theand distribution distribution riverbed permeabiliof of scores scores for forty hydraulicin hydraulic the core gradient, gradient, study areapossible possible were interaction interaction combined zone zone to determinewidthswidths ofof the surfacesurface suitability water, water, andof andinteraction riverbed riverbed permeability intensity permeabili between inty the in coresurface the study core water areastudy and were areagroundwater, combined were combined to as determine shown to indeterminethe Figure suitability 19. the suitability of interaction of interaction intensity between intensity surface between water surface and groundwater,water and groundwater, as shown in as Figure shown 19 . in Figure 19.

Figure 19. Suitability of interaction intensity between surface water and groundwater. Figure 19. Suitability of interaction intensity between surface water and groundwater. Figure 19. Suitability of interaction intensity between surface water and groundwater. AsAs shown shown in in Figure Figure 19, 19 ,the the suitability suitability of of the the interaction interaction intensity intensity between between surface surface water water and and groundwatergroundwaterAs shown is is gradein grade Figure IV IV and 19, and gradethe grade suitability V V at at the the Fuyuof Fuyu the pa partinteractionrt and and the the Jilinintensity Jilin part, part, betweenrespectively, respectively, surface of of the thewater Second Second and SonghuagroundwaterSonghua River; River; is ingrade in other other IV parts and parts gradeof of the the Vriver riverat the the the Fuyu suit suitability abilitypart and of of theinteraction interaction Jilin part, is is respectively,superior superior to to grade of grade the III. Second III. The The suitabilitySonghuasuitability River;of of the the ininteraction interaction other parts intensity intensity of the riverbetween between the surfacesuit surfaceability water water of interaction and and groundwater groundwater is superior at at most mostto grade parts parts III. of of Thethe the YitongsuitabilityYitong River River of andthe and interactionYinma Yinma River River intensity is is inferior inferior between to to grade grade surface III, III, exceptwater except andat at the thegroundwater Changchun Changchun at part partmost of of partsthe the Yitong Yitongof the RiverYitong and River the middleand Yinma part Riverbetween is inferior Jiutai and to gradeDehui III,of theexcept Yinma at theRiver, Changchun where the part suitability of the Yitongof the interactionRiver and theintensity middle between part between surface Jiutai water and and Dehui groundwater of the Yinma is grade River, III. where the suitability of the interaction intensity between surface water and groundwater is grade III. 4.2.4. The Exploitation Condition of Groundwater Resources 4.2.4.The The variation Exploitation of groundwater Condition of depth Groundwater is shown as Resources Figure 20, respectively. The groundwater depth in theThe core variation study ofarea groundwater is generally depth less is than shown 15 as m, Figure which 20, meetsrespectively. the criteria The groundwater for groundwater depth exploitationin the core andstudy is beneficialarea is generally to the construction less than of15 RBF m, works.which meets the criteria for groundwater exploitation and is beneficial to the construction of RBF works.

Water 2016, 8, 176 16 of 24

River and the middle part between Jiutai and Dehui of the Yinma River, where the suitability of the interaction intensity between surface water and groundwater is grade III.

4.2.4. The Exploitation Condition of Groundwater Resources

Water 2016,The 8, 176 variation of groundwater depth is shown as Figure 20, respectively. The groundwater depth16 of 24 Water in2016 the, 8, core 176 study area is generally less than 15 m, which meets the criteria for groundwater exploitation16 of 24 and is beneﬁcial to the construction of RBF works.

FigureFigure 20. 20. GroundwaterGroundwater depthdepth distribution. distribution. Figure 20. Groundwater depth distribution.

4.3. The4.3. Comprehensive The Comprehensive Suitab Suitabilityility Evaluation Evaluation of of RBF RBF Sites 4.3. The Comprehensive Suitability Evaluation of RBF Sites The Thevarious various index index scores scores were were integrated integrated using using EquationEquation (1) (1) to to determine determine the the overall overall suitability suitability of locationsTheof locations various in the in index the core core scores study study were area forintegratedfor RBF RBF works works using (Figure (F Eqigure uation21). Five21). (1) typicalFive to determine typical points werepo theints selected overall were to selectedsuitability show to ofshow locationsthe the characteristics characteristics in the core of eachstudy of each grade area grade of for suitability ofRBF suitability works (Table (F (Table12igure). 12).21). Five typical points were selected to show the characteristics of each grade of suitability (Table 12).

Figure 21. Overall suitability of locations within the core study area for RBF works. Figure 21. Overall suitability of locations within the core study area for RBF works. Figure 21. Overall suitability of locations within the core study area for RBF works. Table 12. All single index values and scores for five typical points. Table 12. All single index values and scores for five typical points. Point 1 Point 2 Point 3 Point 4 Point 5

Index * Point 1 Point 2 Point 3 Point 4 Point 5 Index * Value Score Value Score Value Score Value Score Value Score K Value 60 m/d Score 90 Value 60 m/d Score 90 Value 60 m/d Score 90 12.5Value m/d Score 70 12.5Value m/d Score 70 KD 60 17.9 m/d m 90 80 60 20.2 m/d m 90 80 60 21.6 m/d m 90 80 12.5 5.2 m/d m 70 70 12.5 11.9 m/d m 70 80 DR 150×10 17.9 8m m 3/a 100 80 150×10 20.2 8m m 3/a 100 80 150×10 21.6 8m m 3/a 100 80 9×10 5.28 mm 3/a 7070 9×10 11.98 m3 /a 8070 RG 150×10 III8 m3/a 10090 150×10IV8 m3/a 10060 150×10III8 m3/a 10090 9×108III m 3/a 7090 9×10IV8 m 3/a 7060 GS III III 9090 IVIII 6090 IIIIV 9090 IIIIII 9090 IVⅤ −60275 SI − III3.5 9090 −III17.8 9060 −IV5.8 9080 −III3.3 9090 −Ⅴ15.3 −27560 WI strong−3.5 10090 middle−17.8 6080 weak−5.8 8060 −none3.3 9030 −none15.3 6030 WP 7.5strong m/d 100 100 middle 7.5 m/d 10080 3.5weak m/d 60 60 0.0125none m/d 30 30 0.0125none m/d 30 30 PD 7.5 6.6 m/d m 100 90 7.5 7.4 m/d m 100 90 3.5 5.3 m/d m 60 90 0.0125 5.4 mm/d 30 90 0.0125 6.6 mm/d 30 90 ScoreD 6.6 m 92.5 90 7.4 m 83.5 90 5.3 m 77.5 90 5.4 m 69 90 6.6 m 9.25 90 ScoreGrade 92.5I 83.5 II 77.5 III 69 IV 9.25 V Grade I II III IV V * The meaning of indexes is explained in Table 2. * The meaning of indexes is explained in Table 2. Based on the multi-criteria analysis, the suitability of many locations in the study area was classifiedBased as on grade the V.multi-criteria These locations analysis, were the Jilisuitabilityn City reach, of many the Yinma locations River in estuary the study and area the Fuyuwas classifiedCity reach as of grade the Second V. These Songhua locations River, were as the well Jili asn City the wholereach, Yitongthe Yinma River River and estuary the Dehui and City the Fuyureach City reach of the Second Songhua River, as well as the whole Yitong River and the Dehui City reach

Water 2016, 8, 176 17 of 24

Table 12. All single index values and scores for ﬁve typical points.

Point 1 Point 2 Point 3 Point 4 Point 5 Index * Value Score Value Score Value Score Value Score Value Score K 60 m/d 90 60 m/d 90 60 m/d 90 12.5 m/d 70 12.5 m/d 70 D 17.9 m 80 20.2 m 80 21.6 m 80 5.2 m 70 11.9 m 80 R 150ˆ108 m3/a 100 150ˆ108 m3/a 100 150ˆ108 m3/a 100 9ˆ108 m3/a 70 9ˆ108 m3/a 70 G III 90 IV 60 III 90 III 90 IV 60 S III 90 III 90 IV 90 III 90 V ´275 I ´3.5 90 ´17.8 60 ´5.8 80 ´3.3 90 ´15.3 60 W strong 100 middle 80 weak 60 none 30 none 30 P 7.5 m/d 100 7.5 m/d 100 3.5 m/d 60 0.0125 m/d 30 0.0125 m/d 30 D 6.6 m 90 7.4 m 90 5.3 m 90 5.4 m 90 6.6 m 90 Score 92.5 83.5 77.5 69 9.25 Grade I II III IV V * The meaning of indexes is explained in Table2.

Based on the multi-criteria analysis, the suitability of many locations in the study area was classiﬁed as grade V. These locations were the Jilin City reach, the Yinma River estuary and the Fuyu City reach of the Second Songhua River, as well as the whole Yitong River and the Dehui City reach of the Yinma River. These locations are unsuitable as potential RBF sites. The remainder of the study area was classiﬁed with a better than grade III suitability, and should be suitable for locating RBF works.

5. Conclusions Many important factors affect the site selection for RBF works such as groundwater and surface water quantity, current water quality situation, hydraulic interaction degree and exchange relationship between groundwater and surface water. In this research, a multi-criteria index system was developed for the regional assessment of RBF site suitability in the Second Songhua River and Yinma River. The system was based on a detailed analysis of physical geography and geological and hydrogeological conditions (which were considered to be the main influential factors of RBF), as well as on the development and utilization of water resources and water demand. Scoring criteria based on specialist marking methods were used to determine weighting coefficients and weighted scores. The evaluation method was integrated into the spatial analysis features of GIS to determine the distribution of suitable areas for RBF works. By identifying the suitability grade of areas along the Second Songhua River, the regional evaluation system highlights locations that should be targeted for RBF works. The suitability evaluation system developed in this research thus provides a scientific basis for making decisions for regional industry distribution and relevant groundwater development plans. However, this research still has some limitations that must be mentioned here and will be studied further. (1) The evaluation index system to assess RBF site suitability that was established in this research is suitable for use only in the Second Songhua River catchment. Unfortunately, this catchment is not universally representative of other catchments because of its very specific hydrogeological conditions. (2) The index system is not very comprehensive; some factors such as riverbed thickness and river width were missing because of the limited field data in the study area.(3) Some index value such as riverbed permeability was inferred by limited information, and this would bring some uncertainty to the final results. (4) The specialist marking method was adopted to determine the preference weights; the applicability was limited within specific areas. The AHP (Analytic Hierarchy Process) method and Fuzzy theory would be better to adopt in a general index system [27,28]. (5) For the specialist marking method, it is important to perform a sensitivity analysis on the preference weights and provide measures for assessing the sensitivity due to changes in these weights [28,29]. Nevertheless, the primary evaluation principle and the index system are reasonable, and can be used as a scientific reference for any other regional site selection or feasibility research of RBF.

Acknowledgments: This study was supported by Major Science and Technology Program for Water Pollution Control and Treatment (2014ZX07201-010). Water 2016, 8, 176 18 of 24

Author Contributions: Lixue Wang is primarily responsible for implementing the suitability evaluation and preparing manuscript. Xueyan Ye and Xinqiang Du are responsible for establishing the evaluation index system. And meanwhile Xinqiang Du supervised the evaluation process and critically reviewed the draft manuscript. Conﬂicts of Interest: The authors declare to have no conﬂict of interest.

Appendix

Appendix A

Table A1. Environmental quality standards for surface water (GB3838-2002) (Main items). Unit in mg/L.

Classiﬁcation Item NO. Standard Value Grade I Grade II Grade III Grade IV Grade V iIems Saturation rate 1 DOě 6 5 3 2 90% (or 7.5) Potassium 2 permanganate 2 4 6 10 15 indexď 3 CODď 15 15 20 30 40 4 BOD5ď 3 3 4 6 10 5 NH3-Nď 0.15 0.5 1.0 1.5 2.0 0.02 0.1 0.2 0.3 0.4 TP (counted 6 (lake/reservoir (lake/reservoir (lake/reservoir (lake/reservoir (lake/reservoir as P) ď 0.01) 0.025) 0.05) 0.1) 0.2) TN (counted as 7 0.2 0.5 1.0 105 2.0 N) ď 8 Cuď 0.01 1.0 1.0 1.0 1.0 9 Znď 0.05 1.0 1.0 2.0 2.0 Fluoride 10 1.0 1.0 1.0 1.5 1.5 (counted as F) ď 11 Seď 0.01 0.01 0.01 0.02 0.02 12 Asď 0.05 0.05 0.05 0.1 0.1 13 Hgď 0.00005 0.00005 0.0001 0.001 0.001 14 Cdď 0.001 0.005 0.005 0.005 0.01 15 Cr6+ď 0.01 0.05 0.05 0.05 0.1 16 Pbď 0.01 0.01 0.05 0.05 0.1 17 Cyanideď 0.005 0.05 0.2 0.2 0.2 18 Volatile penolď 0.002 0.002 0.005 0.01 0.1 19 petroleumď 0.05 0.05 0.05 0.5 1.0 Anionic 20 0.2 0.2 0.2 0.3 0.3 surfactantď 21 Sulﬁdeď 0.05 0.1 0.2 0.5 1.0 Coliform 22 200 2000 10000 20000 40,000 (number/L) ď Water 2016, 8, 176 19 of 24

Table A2. Quality standard for groundwater (GB/T 14848-93).

Items Items Class I Class II Class III Class IV Class V NO. 1 Color (degree) ď5 ď5 ď15 ď25 >25 2 Odor and taste None None None None None 3 Turbidity (degree) ď3 ď3 ď3 ď10 >10 4 Visible matters (unaided eye) None None None None None 5 pH 6.5–8.5 5.5–6.5; 8.5–9 <5.5, >9 Total hardness (counted as 6 ď150 ď300 ď450 ď550 >550 CaCO3) (mg/L) 7 TDS (mg/L) ď300 ď500 ď1000 ď2000 >2000 8 Sulfate (mg/L) ď50 ď150 ď250 ď350 >350 9 Chloride (mg/L) ď50 ď150 ď250 ď350 >350 10 Fe (mg/L) ď0.1 ď0.2 ď0.3 ď1.5 >1.5 11 Mn (mg/L) ď0.05 ď0.05 ď0.1 ď1.0 >1.0 12 Cu (mg/L) ď0.01 ď0.05 ď1.0 ď1.5 >1.5 13 Zn (mg/L) ď0.05 ď0.5 ď1.0 ď5.0 >5.0 14 Mo (mg/L) ď0.001 ď0.01 ď0.1 ď0.5 >0.5 15 Co (mg/L) ď0.005 ď0.05 ď0.05 ď1.0 >1.0 Volatile phenolic (counted as 16 ď0.001 ď0.001 ď0.002 ď0.01 >0.01 phenol) (mg/L) Anion synthetic detergent Not 17 ď0.1 ď0.3 ď0.3 >0.3 (mg/L) detected Potassium permanganate 18 ď1.0 ď2.0 ď3.0 ď10 >10 index (mg/L) Nitrate (counted as N) 19 ď2.0 ď5.0 ď20 ď30 >30 (mg/L) Nitrite (counted as N) 20 ď0.001 ď0.01 ď0.02 ď0.1 >0.1 (mg/L) Ammonia nitrogen (NH4) 21 ď0.02 0.02 ď0.2 ď0.5 >0.5 (mg/L) 22 Fluoride (mg/L) ď1.0 ď1.0 ď1.0 ď2.0 >2.0 23 Iodide (mg/L) ď0.1 ď0.1 ď0.2 ď1.0 >1.0 24 Cyanide (mg/L) ď0.001 ď0.01 ď0.05 ď0.1 >0.1 25 Hg (mg/L) ď0.00005 ď0.0005 ď0.001 ď0.001 >0.001 26 As (mg/L) ď0.005 ď0.01 ď0.05 ď0.05 >0.05 27 Se (mg/L) ď0.01 ď0.01 ď0.01 ď0.1 >0.1 28 Cd (mg/L) ď0.0001 ď0.001 ď0.01 ď0.01 >0.01 29 Cr (sexavalence) (mg/L) ď0.005 ď0.01 ď0.05 ď0.1 >0.1 30 Pb (mg/L) ď0.005 ď0.01 ď0.05 ď0.1 >0.1 31 Be (mg/L) ď0.00002 ď0.0001 ď0.0002 ď0.001 >0.001 32 Ba (mg/L) ď0.01 ď0.1 ď1.0 ď4.0 >4.0 33 Ni (mg/L) ď0.005 ď0.05 ď0.05 ď0.1 >0.1 Not 34 DDD (µg/L) ď0.005 ď1.0 ď1.0 >1.0 detected Hexachloro-cyclohexane 35 ď0.005 ď0.05 ď5.0 ď5.0 >5.0 soprocide (µg/L) 36 Coliform (number/L) ď3.0 ď3.0 ď3.0 ď100 >100 37 Total bacteria (number/L) ď100 ď100 ď100 ď1000 >1000 38 Total α radioactivity (Bq/L) ď0.1 ď0.1 ď0.1 >0.1 >0.1 39 Total β radioactivity (Bq/L) ď0.1 ď1.0 ď1.0 >1.0 >1.0 Water 2016, 8, 176 20 of 24

WaterAppendix 2016, 8 , B.176 Distribution figures of all evaluation index scores. 20 of 24

Appendix B. Distribution figures of all evaluation index scores. Water 2016, 8, 176 20 of 24 Water 2016, 8, 176 20 of 24

AppendixAppendix B. Distribution B. Distribution figures ﬁgures of of all all evaluation evaluation index scores.scores.

Figure A1. Distribution of hydraulic conductivity scores.

Figure A2. Distribution of aquifer thickness scores. Figure A2. Distribution of aquifer thickness scores. Figure A2. Distribution of aquifer thickness scores.

Figure A2. Distribution of aquifer thickness scores.

Figure A3. Distribution of annual average runoff scores. Figure A3. Distribution of annual average runoff scores.

Figure A3. Distribution of annual average runoff scores.

Water 2016, 8, 176 21 of 24

Water 2016Water, 82016, 176, 8 , 176 21 of21 24 of 24

Figure A4. Distribution of groundwater quality scores.

Figure A4. Distribution of groundwater quality scores. Figure A4. Distribution of groundwater quality scores. Figure A4. Distribution of groundwater quality scores.

Figure A5. Distribution of surface water quality scores. Figure A5. Distribution of surface water quality scores. Figure A5. Distribution of surface water quality scores.

Figure A5. Distribution of surface water quality scores.

Figure A6. Distribution of hydraulic gradient scores.

Water 2016, 8, 176 22 of 24

Water 2016, 8, 176 22 of 24 Water 2016, 8, 176 22 of 24

Figure A7. Distribution of scores for the possible.

Figure A7. Distribution of scores for the possible. Figure A7. Distribution of scores for the possible.

Figure A7. Distribution of scores for the possible.

Figure A8. Distribution of riverbed permeability scores.

Figure A8. Distribution of riverbed permeability scores. Figure A8. Distribution of riverbed permeability scores.

Figure A8. Distribution of riverbed permeability scores.

Figure A9. Distribution of the groundwater depth scores inﬂuence zone width of surface water. Figure A9. Distribution of the groundwater depth scores influence zone width of surface water.

Figure A9. Distribution of the groundwater depth scores influence zone width of surface water.

Water 2016, 8, 176 23 of 24

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