Simulation and Parameter Law of HEC-HMS for Multi-Source Flood in Arid Region Based on Three-Dimensional Classification Criteria: A Case Study of Manas River Basin

With the acceleration of urbanization in a river basin, the changes in the underlying surface structure of the basin are more and more intense, which causes frequent floods. This article aims to analyze the applicability of the HEC-HMS model in flood simulation in urbanization basins and the influence of land use changes on catchment runoff. Pu River Basin is a typical urbanization basin and is taken as the research project. Based on land use changes, soil types, and long-term hydrological data in the Pu River Basin, the HEC-HMS hydrological model is constructed using GIS and HEC-geoHMS. Then, the relative error of flood peak and runoff, Nash–Sutcliffe efficiency coefficient, and correlation are used to evaluate the model simulation rating. The results show that the HEC-HMS model is suitable for an urbanization basin, and its performance grade before urbanization is better than that after urbanization. Finally, sensitivity analysis of nine parameters on model performance shows that curve number, initial abstraction, imperviousness, and time lag are the main parameters. The research results will provide a reference for urbanization basins’ flood simulation and stormwater management.

علاوه بر تغییر‌اقلیم، تغییر‌کاربری‌اراضی به عنوان یک عامل جانبی اثرات مهمی بر سیلاب دارد. لذا پیش-بینی اثر این دو پارامتر بر وضعیت سیلاب دهه‌های آتی، راهگشای مقابله با این پدیده خواهد بود. هدف از مطالعه حاضر پیش‌بینی وضعیت هیدرولوژیکی حوزه آبخیز اسکندری در دهه آتی تحت اثر تغییر‌اقلیم و تغییر‌کاربری‌اراضی می‌باشد. جهت بررسی تغییرات اقلیمی دهه 2020، برونداد مدل HadCM3 تحت سناریوهای A2 و B1 توسط مدل LARS-WG ریزمقیاس گردید. پس از بررسی تغییرات کاربری-اراضی گذشته، دو سناریو جهت پیش‌بینی تغییرات آن در آینده طراحی شد. در انتها با تغییر هایتوگراف بارش و کاربری‌اراضی در مدلHEC-HMS که برای دوره گذشته کالیبره و اعتبارسنجی شده، اثر تغییر اقلیم و کاربری اراضی بر سیلاب منطقه مطالعاتی مورد بررسی قرار گرفته شد. نتایج نشان دهنده افزایش 2/7 تا 9/10 درصدی بارش متوسط سالانه دهه 2020 می‌باشد. افزایش توأمان دمای حداقل و حداکثر منطقه مطالعاتی در تمامی ماه‌ها موجب افزایش 82/0 تا 02/1 درجه سانتی‌گرادی دمای متوسط سالانه خواهد شد. افزایش دبی اوج و حجم سیلاب در ماه‌های مارس، اکتبر و فوریه و کاهش آن در ماه آوریل پیش بینی شده است. به طوری که در صورت تغییر‌کاربری‌اراضی همراه با تغییر‌اقلیم این افزایش شدیدتر خواهد بود.

Taking Jinjiang watershed of Fujian province in China as study area, this work examines the effects of DEM resolutions, ranging from 30m to 600m, on Nash efficiencies of rainstorm flood simulation based on HEC-HMS model. Another focus is the influence of sub-basin division on flood simulation results. The study indicates that, with the decreasing of DEM resolution, basin slope, among other parameters such as basin evaluation and river length, etc., is most sensitive to the change of DEM resolution. In general, the Nash efficiency would drop down if DEM resolution decreases while other parameters held constant. DEM resolution at 150m appears to play a role of critical and optimal scale. Being based on 30m DEM resolution, it is found that the change of divided sub-basin number only slightly affects the results of flood simulation.

流域土地利用变化对不同重现期洪水的影响——以奉化江皎口水库流域为例

The rivers in the hill area have a larger drop, and heavy rains are liable to form mountain floods. Flood calculation in small watershed is a key link in the prevention of flash floods. Taking the Xueye Lake basin in Laicheng District as the research object, HEC-HMS was used to establish the semi-distributed hydrological model of the hill basin to calculate the rainfall-runoff and flood routing process. Based on the historical flood elevations of three typical floods, the sub-basin parameters were calibrated using the trial-and-error method. According to the flow data of the basin outlet, the peak-weighted RMS error function was selected as the objective function, and the Nelder-Mead optimization algorithm was used to estimate the overall watershed parameters. Rainfall and flow data for two floods were used to verify model accuracy. The results show that the relative errors between peak discharge and runoff depth are less than 20%. The model has good applicability to the flood simulation of the Xueye Lake Basin and can play an actual role in the mountain flood warning forecast. The proposed lumped parameter calibration and modeling method can provide reference for flood simulation in other small basins.

Human activities and climate change have significantly influenced the water cycle, impacting flood risks and water security. This study centers on the Jing River Basin in the Chinese Loess Plateau, analyzing hydrological patterns and flood progression using the HEC-HMS model under changing conditions. The findings indicate that climate change substantially affects flood predictions, increasing peak flows and volumes by up to 10.9% and 11.1%, respectively. It is essential to recognize that traditional flood models may underestimate the risks posed by these changes, emphasizing the necessity for updated methods incorporating climatic and human factors. Changes in land use, such as the expansion of grasslands and forests, have reduced peak discharges and flood volumes. Consequently, the combined impacts of climate and land use changes have intensified flood frequencies, necessitating updated strategies to manage risks effectively. The dynamics of flooding are significantly impacted by changes in climate and land use, particularly in minor floods that occur frequently, highlighting the influence of climate change on flooding trends. Within the Jing River Basin, hydrological patterns have been shaped by both climatic variations and human activities, leading to an increase in extreme hydrological events and concerns regarding water security. Using the HEC-HMS model, this study examines the hydrology of the Jing River Basin, focusing on the design of storm events and analyzing various flood characteristics under different scenarios. Climate change has resulted in higher peak discharges and volume surges ranging from 6.3% to 10.9%, while shifts in land use, such as decreases in farmland and the expansion of grasslands, have caused declines ranging from 7.2% to 4.7% in peak flows and volumes. The combined effects of climate variation and land utilization have complex implications for flood patterns, with milder to moderate floods showing a more significant impact and shorter return periods facing increased consequences. These findings underscore the interconnected nature of climate change, land use, and flooding dynamics in the Jing River Basin, highlighting the need for comprehensive strategies to address these challenges and ensure sustainable water management in the region.

Hydrological modeling is a commonly used tool by water resource planners to simulate the hydrological response in a basin due to precipitation for the purpose of management of basin water. With the increasing demand for limited water resources in every basin, careful management of water resources becomes more important. The Deduru Oya river in Sri Lanka supplies water to number of new and ancient irrigation systems and the management of water resources in the Deduru Oya river basin, which has an area of 2620 km2, is important for optimum utilization of water for these irrigation systems. This paper describes a case study of continuous rainfall-runoff modeling in part of the Deduru Oya basin with intra-basin diversions and storage irrigation systems using the Hydrologic Engineering Center – Hydrologic Modeling System (HEC–HMS) version 3.0.1 to estimate runoff in the Deduru Oya river. Long term daily rainfall data at several rain gauging stations, evaporation, land use and soil data in the river basin, daily river runoff at a stream gauging station, intra-basin diversions from the river into a storage reservoir, irrigation releases from the reservoir and drainage flow returned to the river from irrigation systems were used to set up the HEC-HMS model. Five-layer soil moisture accounting loss method, Clark unit hydrograph transformation method, and recession base flow method of the HEC-HMS model were used. Temporally varying irrigation water uses, storages and losses in the basin were taken into account in the analysis. The results depict the capability of HEC–HMS to reproduce stream flows in the basin to a high accuracy with averaged computed Nash Sutcliffe efficiencies of 0.80. The study demonstrates potential HEC–HMS application in flow estimation from tropical catchments with intra-basin diversions and irrigation storages. The model developed is a tool for water management in the Deduru Oya river basin. ENGINEER, Vol. 48, No.01, pp. 1-9, 2015

The process of urbanization with increasing population and development has drastically disrupted the water balance of natural catchment. The variation in hydrological responses due to rainfall and land use changes increases the difficulty on rainfall-runoff modelling. In addition, large uncertainties in rainfall data can be a significant source of error in flood simulation. Thus, the objective of this study is to compare the temporal resolution effects between 15 min and 1- hour rainfall data on hydrological modelling at urban catchment. 15 min and 1-hour resolution rainfall data was collected from eight rainfall stations at Penchala River catchment. The temporal resolution effects of rainfall data on hydrological modelling were assessed by comparing 15 min resolution and 1-hour resolution rainfall data using HEC-HMS model. The modelling results showed that average peak discharge percentage errors for 1-hour rainfall interval is 15.79 %, whereas 4.33% for 15 minutes’ rainfall interval. The fine resolution rainfall data has proved that it had improved the performance of hydrological modelling using HEC-HMS model. For model calibration, the mean percentage errors for peak discharge and runoff volume were found to be 4.33% and 20.88%, respectively. Meanwhile, the mean percentage errors for peak discharge and runoff volume for model validation were found to be 16.25% and 16.51%, respectively.

Affected by human activities, land use and land cover has changed in Daqinghe watershed, China, which resulted in varied runoff. In many hydrological stations, there was a decreasing trend of flood volume and flood peak, but no trend of rainfall depth. In order to quantify the effect of land use change on flood peak and volume, we selected 5 sub-watersheds in Daqinghe watershed, and made a multi-linear regression analysis incorporating the main information in the selected sub-watersheds. The dependent variables are changes in flood volume and flood peak, and the independent variables are the control factors including changes in rainfall depth, intensity, land use area, watershed area, and so on. The rainfall and flood data series are from 1956 to 2005. We divided the data into 2 groups according to flood size―greater than and less than 10 year return period. At last, 4 regression equations were obtained. Based on the multi-linear regression equations and land use data of 1970, 1980, 1995 and 2000, the quantified effects of land use change on flood peak and volume were obtained. Compared with 2000 land use condition, flood volume and peak varied larger in 1970 and 1995 land use conditions, but slightly in 1980 land use condition. Take Zijingguan as an example, flood volume greater than 10 year return period increased 4.08 mm in 1970 land use and decreased 4.90 mm in 1995 land use, but just increased 0.12 mm in 1980 land use. Among all the selected sub-watersheds, land use change had a significant effect on both flood volume and peak in Zijingguan and Zhangfang sub-watersheds. And Manshuihe showed a large variation in 1970 land use condition, other sub-watersheds exhibit a moderate variation due to land use change.

To explore the applicability of HEC-HMS and its parameter regionalization in small ungauged watersheds in hilly areas, this paper takes hydrological divisions III and IV of Henan Province as the research area. The HEC-HMS model is applied to three typical small watersheds in Luanchuan, Gaocheng and Xiahecun. On the basis of verifying the validity of the model, the regression relationships between model parameters and underlying surface characteristics are established and verified in the Zhongtang small watershed. The results show that the qualified rates of runoff depth, flood peak flow, peak occurrence time and NSE in flood simulation are higher than 75%, and the accuracy reaches the grade B level regardless of the HEC-HMS model test or the parameter regionalization method verification. In summary, the HEC-HMS model can be applied to simulate the rainfall-runoff process of small watersheds in hilly areas, and the parameter regionalization method can effectively deduce the model parameters of HEC-HMS for small ungauged watersheds in hilly areas.

Prediction of hydrological responses to land use change

With the advancement of society and the impact of various factors such as climate change, surface conditions, and human activities, there has been a significant increase in the frequency of extreme rainfall events, leading to substantial losses from flood disasters. The presence of numerous small and medium-sized water conservancy projects in the basin plays a crucial role in influencing runoff production and rainwater confluence. However, due to the lack of extensive historical hydrological data for simulation purposes, it is challenging to accurately predict floods in the basin. Therefore, there is a growing emphasis on flood simulation and forecasting that takes into account the influence of upstream water projects. Moushan Reservoir basin is located in a hilly area of an arid and semi-arid region in the north of China. Flooding has the characteristics of sudden strong, short confluence time, steep rise, and steep fall, especially floods caused by extreme weather events, which have a high frequency and a wide range of hazards, and has become one of the most threatening natural disasters to human life and property safety. There are many small and medium-sized reservoirs in this basin, which have a significant influence on the accuracy of flood prediction. Therefore, taking Moushan Reservoir as an example, this paper puts forward a flash flood simulation method for reservoirs in hilly areas, considering upstream reservoirs, which can better solve the problem of flood simulation accuracy. Using the virtual aggregation method, the 3 medium-sized reservoirs and 93 small upstream reservoirs are summarized into 7 aggregated reservoirs. Then, we construct the hydrological model combining two method sets with different runoff generation and confluence mechanisms. Finally, after model calibration and verification, the results of different methods are analyzed in terms of peak discharge error, runoff depth error, difference in peak time, and certainty coefficient. The results indicate that the flooding processes simulated by the proposed model are in line with the observed ones. The errors of flood peak and runoff depth are in the ranges of 2.3% to 15% and 0.1% to 19.6%, respectively, meeting the requirements of Class B accuracy of the “Water Forecast Code”. Method set 1 demonstrates a better simulation of floods with an average flood peak error of 5.63%. All these findings illustrate that the developed model, utilizing aggregate reservoirs and dynamic parameters to reflect regulation and storage functions, can effectively capture the impact of small water conservancy projects on confluence. This approach addresses challenges in simulating floods caused by small and medium-sized reservoirs, facilitating basin-wide flood prediction.

Changes in land use and land cover (LULC) and climate increasingly influence flood occurrences in the Gumara watershed, located in the Upper Blue Nile (UBN) basin of Ethiopia. This study assesses how these factors impact return period-based peak floods, flood source areas, and future high-flow extremes. Merged rainfall data (1981–2019) and ensemble means of four CMIP5 and four CMIP6 models were used for historical (1981–2005), near-future (2031–2055), and far-future (2056–2080) periods under representative concentration pathways (RCP4.5 and RCP8.5) and shared socioeconomic pathways (SSP2-4.5 and SSP5-8.5). Historical LULC data for the years 1985, 2000, 2010, and 2019 and projected LULC data under business-as-usual (BAU) and governance (GOV) scenarios for the years 2035 and 2065 were used along with rainfall data to analyze flood peaks. Flood simulation was performed using a calibrated Hydrologic Engineering Center–Hydrologic Modeling System (HEC-HMS) model. The unit flood response (UFR) approach ranked eight subwatersheds (W1–W8) by their contribution to peak flood magnitude at the main outlet, while flow duration curves (FDCs) of annual maximum (AM) flow series were used to analyze changes in high-flow extremes. For the observation period, maximum peak flood values of 211.7, 278.5, 359.5, 416.7, and 452.7 m3/s were estimated for 5-, 10-, 25-, 50-, and 100-year return periods, respectively, under the 2019 LULC condition. During this period, subwatersheds W4 and W6 were identified as major flood contributors with high flood index values. These findings highlight the need to prioritize these subwatersheds for targeted interventions to mitigate downstream flooding. In the future period, the highest flow is expected under the SSP5-8.5 (2056–2080) climate scenario combined with the BAU-2065 land use scenario. These findings underscore the importance of strategic land management and climate adaptation measures to reduce future flood risks. The methodology developed in this study, particularly the application of RF-MERGE data in flood studies, offers valuable insights into the existing knowledge base on flood modeling.

Watershed hydrological modeling methods are currently the predominant approach for flood forecasting. Digital elevation model (DEM) data, a critical input variable, significantly influence the accuracy of flood simulations, primarily due to their resolution. However, there is a paucity of research exploring the relationship between DEM resolution and flood simulation accuracy. This study aims to investigate this relationship by examining three watersheds of varying scales in southern Jiangxi Province, China. Utilizing the Liuxihe model, a new-generation physically based distributed hydrological model (PBDHM), we collected and collated data, including DEM, land use, soil type, and hourly flow and rainfall data from monitoring stations, covering 22 flood events over the last decade, to conduct model calibration and flood simulation. DEM data were processed into seven resolutions, ranging from 30 m to 500 m, to analyze the impact of DEM resolution on flood simulation accuracy. The results are as follows. (1) The Nash–Sutcliffe efficiency coefficients for the entire set of flood events were above 0.75, demonstrating the Liuxihe model’s strong applicability in this region. (2) The DEM resolution of the Anhe and Dutou watersheds lost an average of 7.9% and 0.8% accuracy when increasing from 30 m to 200 m, with further losses of 37.9% and 10.7% from 200 m to 300 m. Similarly, the Mazhou watershed showed an average of 8.4% accuracy loss from 30 m to 400 m and 20.4% from 400 m to 500 m. These results suggest a threshold where accuracy sharply declines as DEM resolution increases, and this threshold rises with watershed scale. (3) Parameter optimization in the Liuxihe model significantly enhanced flood simulation accuracy, effectively compensating for the reduction in accuracy caused by increased DEM resolution. (4) The optimal parameters for flood simulation varied with different DEM resolutions, with significant changes observed in riverbed slope and river roughness, which are highly sensitive to DEM resolution. (5) Changes in DEM resolution did not significantly impact surface flow production. However, the extraction of the water system and the reduction in slope were major factors contributing to the decline in flood simulation accuracy. Overall, this study elucidates that there is a threshold range of DEM resolution that balances data acquisition efficiency and computational speed while satisfying the basic requirements for flood simulation accuracy. This finding provides crucial decision-making support for selecting appropriate DEM resolutions in hydrological forecasting.

Modelling the impact land use change on flood risk: Umia (Spain) and Voglajna (Slovenia) case studies