• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• 제2권4호
• /
• pp.235-246
• /
• 2021

This study investigated the impact of baseflow on fish community in the Ungcheon stream (16.5 km long) located downstream of the Boryeong Dam, Korea. Based on field monitoring, there were five dominant fish species in the Ungcheon Stream accounting for 75% of the total fish community: Zacco platypus, Zacco koreanus, Tridentiger brevispinis, Rhinogobius brunneus, and Pungtungia herzi. These five fish species were selected as target species. HydroGeoSphere (HGS) and River2D models were used for hydrologic and hydraulic simulations, respectively. A habitat suitability index model was used to simulate fish habitat. To assess the impact of baseflow, each representative discharge was examined with or without baseflow. The HGS model was used to calculate baseflow within the study reach. This baseflow was observed to increase gradually with longitudinal distance. Validation of the hydraulic model dem onstrated that computed water surface elevated when baseflow was included, which was in good agreement with measured data, as opposed to the result when baseflow was excluded. Composite suitability index distributions and weighted usable area in the study reach were presented for target species. Simulations indicated that the baseflow significantly increased habitat suitability for the entire fish community. These results demonstrate that there should be a substantial focus on the baseflow for physical habitat simulation.

• 한국농공학회논문집
• /
• 제59권2호
• /
• pp.1-11
• /
• 2017

The analysis of baseflow contribution is very significant in Korea because most rivers have high variability of streamflow due to the monsoon climate. Recently, the importance of such analysis is being more evident especially in terms of river management because of the changing pattern of rainfall and runoff resulted from climate change. Various baseflow separation methods have been developed to separate baseflow from streamflow. However, it is very difficult to identify which method is the most accurate way due to the lack of measured baseflow data. Moreover, it is inappropriate to analyze the annual baseflow contribution for Korean rivers because rainfall patterns varies significantly with the seasons. Thus, this study compared the baseflow contributions at various time-scales (annual, seasonal and monthly) for the 4 major river basins through BFI (baseflow index) and suggested baseflow contribution of each basin by the BFI ranges searched from different baseflow separation methods (e.g., BFLOW, HYSEP, PART, WHAT). Based on the comparison of baseflow contributions at the three time scales, this study showed that the baseflow contributions from the monthly and seasonal analysis are more reasonable than that from the annual analysis. Furthermore, this study proposes that defining BFI with its range is more proper than a specific value for a watershed, considering the difference of BFIs between various baseflow separation methods.

• 한국농공학회논문집
• /
• 제60권3호
• /
• pp.95-105
• /
• 2018

Understanding the composition of the dam inflow can improve the efficiency of dam operation considering the seasonal characteristics. Hydrograph analysis is one of the methods to identify the characteristics of dam inflow. In addition, baseflow separation on the dam inflow can be affected by anthropogenic influences depending on dam locations. In this regard, the objectives of this study are 1) to analyze yearly and monthly baseflow contribution to the dam inflow and 2) to compare the baseflow contribution to the inflow in dams located upstream and downstream of the watershed. The result shows that the estimated baseflow index was smaller in the upstream dams compared to the downstream dams. Discharge from the upstream water infrastructure including dams and reservoirs can be a part of inflow into the downstream water infrastructure. Based on this scenario, the discharge regulated from the upstream dam could lead to overestimation of baseflow contribution to inflow into the downstream dam. We expect that the results from this study elucidate the role and function of dams and hence, contribute to the efficient operation of dams located in the upstream and the downstream of the watershed.

• 한국수자원학회논문집
• /
• 제52권2호
• /
• pp.97-105
• /
• 2019

본 연구에서는 SWAT 모형과 PART 방법을 이용하여 낙동강 유역과 전국 하천을 대상으로 기저유출지표를 산정하고, 도시화에 따른 기저유출 영향을 분석하였다. 낙동강 유역의 연평균 기저유출은 총유량 대비 약 40-44%인 것으로 분석되었으며, 계절별로는 12월과 1월 겨울철에 90%를 상회하는 것으로 나타났다. 또한 전국 317개소 관측 유량에 대해 기저유출을 분석한 결과 기저유출이 전국하천 유량에 기여하는 비율은 연평균 약 40%인 것으로 나타났으며, 지역별로 20% 미만~80% 이상인 것으로 예측되었다. 따라서 기저유출지표가 적은 지역에서는 주변 생태계 보전을 위해 지하수 이용과 개발을 제한하는 것이 타당할 것이다. 한편 금호강 유역을 대상으로 동일 기상조건에서 1975년과 2000년도 토지이용변화에 따른 기저유출 감소가 하천유량에 미치는 영향을 분석하였으며, 그 결과 도시화율 증가에 의해 하천유지유량의 경우 미달일수가 19일~24일 정도 증가하는 것으로 분석되었다.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2022년도 학술발표회
• /
• pp.149-149
• /
• 2022

Accurate quantitative evaluation of baseflow contribution to streamflow is imperative to address seasonal drought vulnerability, flood occurrence and groundwater management concerns for efficient and sustainable water resources management in watersheds. Several baseflow separation algorithms using recursive filters, graphical method and tracer or chemical balance have been developed but resulting baseflow outputs always show wide variations, thereby making it hard to determine best separation technique. Therefore, the current global shift towards implementation of artificial intelligence (AI) in water resources is employed to compare the performance of deep learning models with conventional hydrograph separation techniques to quantify baseflow contribution to streamflow of Piney River watershed, Tennessee from 2001-2021. Streamflow values are obtained from the USGS station 03602500 and modeled to generate values of Baseflow Index (BI) using Web-based Hydrograph Analysis (WHAT) model. Annual and seasonal baseflow outputs from the traditional separation techniques are compared with results of Long Short Term Memory (LSTM) and simple Gated Recurrent Unit (GRU) models. The GRU model gave optimal BFI values during the four seasons with average NSE = 0.98, KGE = 0.97, r = 0.89 and future baseflow volumes are predicted. AI offers easier and more accurate approach to groundwater management and surface runoff modeling to create effective water policy frameworks for disaster management.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2018년도 학술발표회
• /
• pp.171-171
• /
• 2018

댐 유입량의 구성을 이해하는 것은 직접유출과 기저유출의 특성에 따라 수자원확보, 물 공급, 관개용수, 수력발전, 생태계 서식지, 친수활동 등 계절별 댐 운영을 효율적으로 수행하는데 기여할 수 있다. 또한, 댐은 대부분 유역 상류에 위치해 있어 댐 유입유량에 있어 다른 수리구조물에 의한 영향이 상대적으로 작기 때문에 앞에서 제시한 인위적 영향을 제외한 기저유출분리를 수행 할 수 있다. 이와 관련하여 본 연구의 목적은 1)댐 유입량에 대한 연별, 월별 기저유출을 분석하고; 2) 유역 상 하류에 위치한 댐의 유입량에 대하여 기저유출 기여도를 비교하는 것이다. 두 개의 연계 댐에 대하여 인위적 영향이 적은 상류에 위치한 댐이 하류에 위치한 댐보다 Baseflow Index가 더 작은 결과를 보여주었다. 상류 수자원시설부터 인위적 방류는 하류의 댐 유입량의 Baseflow Index를 과다산정의 원인이 될 수 있다는 것으로 나타났다. 본 연구의 결과는 댐 유입량의 특성을 월별 연별로 분석함으로써 댐의 역할과 기능을 확대하고 효율적 상 하류 댐 연계운영에 기여할 것으로 기대한다.

• 한국수자원학회논문집
• /
• 제48권4호
• /
• pp.309-319
• /
• 2015

국내 하천특성은 기후변화에 의한 계절별 기후변동성과 급속한 경제성장으로 인한 급격한 토지피복의 변화에 의하여 영향을 받아왔다. 이와 관련하여, 하천관리는 수자원이용 등 인간의 활동 뿐 아니라 생태계측면에서도 그 중요성이 커지고 있다. 하천관리의 첫 번째 단계인 직접유출과 기저유출을 포함한 하천특성을 이해하는 것은 지속적인 하천환경을 조성하기 위하여 지대한 기여를 할 수 있다. 그러므로 본 연구의 목적은 효율적인 하천관리를 위해 직접유출과 기저유출을 정량화하여 하천에 미치는 기여도를 산정하는 것이다. 이를 위하여 한강수계에 위치한 71개의 유량관측소에 대하여 BFLOW와 WHAT 프로그램을 이용하여 기저유출 분리를 수행하였다. 그 결과 한강수계의 기저유출비는 0.42에서 0.78의 범위를 가지며, 기저유출비가 50%를 넘는 관측소는 전체 관측소의 76%를 차지하였다. 그러나 산출된 기저유출비는 댐, 저수지, 호수로부터의 방류량과 같은 인위적 영향 때문에 과다산정 되었을 가능성이 있다. 본 연구는 추후 국가적 차원에서 하천관리의 효율성과 안전성을 개선하기 위하여 전략적으로 하천 기능을 조절하는데 기여를 할 것으로 기대한다.

• 한국농공학회논문집
• /
• 제58권1호
• /
• pp.27-38
• /
• 2016

More severe and frequent flood and drought have increased the attentions on the river management. In particular, baseflow is an important element among many streamflow characteristics because streamflow is mainly consisted of direct runoff and baseflow. In this regard, this study attempted to analyze the relationship between streamflow variability and baseflow contributions on Nakdong river basin. For this, two Streamflow Variability Indices (SVI) were used: Coefficient of Variation (CV) and Coefficient of Flow Regime (CFR). Furthermore, baselow separation was individually conducted by three methods (PART, WHAT and BFLOW), and based on this, Baseflow Index (BFI) was calculated. Also, we used the daily streamflow data retrieved from 27 gauge stations in Nakdong river basin for baseflow separation. The results showed that BFI calculated by three models ranges from 0.14 to 0.90 for 27 gauge stations. For SVI, BFI has much higher correlation with CV than with CFR. Also, the inversely proportional relationship between BFI and CV showed that higher baseflow contribution, less streamflow variability.

• 대한지하수환경학회지
• /
• 제7권1호
• /
• pp.15-19
• /
• 2000

본 연구는 하천유량 수문곡선의 분리를 통한 기저유량 산정에 관한 것이다. 수문곡선을 분리하기 위하여 Institute of Hydrology(1980)에서 제안한 표준방법(Standard Method)을 이용하였다. 이를 위하여 대상유역의 유역특성치와 기저유출관계를 이용하여 모형의 매개변수를 산정하였으며, 그 결과를 토대로 수문곡선을 분리하여 기저유량을 산정 하였다. 기저유량 산정결과 기저 유출율은 20.0%∼39.4%로 나타났으며, 유역면적이 비교적 큰 유역에서는 기저 유출율이 다소 높게 나타났고, 상대적으로 유역면적이 적은 지역에서는 기저 유출율이 적게 나타났다. 그리고 연 강우량과 기저 유출율의 관계를 분석한 결과 연강우량과 기저 유출율의 상관성은 거의 나타나지 않았다.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2022년도 학술발표회
• /
• pp.135-135
• /
• 2022

In this study, we evaluated uncertainties in baseflow separation filter methods focusing on changes in recession constant (𝛼) values, which include Lynie & Holick (LH) algorithm, Chapman algorithm, Eckhardt filter, and EWMA filter. Here, we analyzed daily streamflow data at 14 stations in the Urmia Lake basin, Iran, from 2015 to 2019. The 𝛼 values were computed using three different approaches from calculating the slope of a recession curve by averaging the flow over all seasons, a correlation method, and a mean value of the ratio of Q_t+1 to Q_t. In addition to the 𝛼 values, the BFImax (maximum value of the baseflow index (BFI)) was determined for the Eckhardt filter through the backward filter method. As results, it indicates that the estimated baseflow is dependent upon the selection of filter methods, their parameters, and catchment characteristics at different stations. In particular, the EWMA filter showed the least changes in estimating the baseflow value by changing the 𝛼 value, and the Eckhardt filter and LH algorithm showed the highest sensitivity to this parameter at different stations.