River Levees Research Articles

Vegetation and its relationship with geomorphologic units in the Parana River floodplain, Argentina

The Parana River is one of the most important fluvial systems of South America and its floodplain includes the most diverse subtropical ecosystem on the continent. However, the relationship between basic aspects, such as the vegetation and geomorphology of the river floodplain, has scarcely been investigated. In this paper, the annual dynamics of vegetation in relation to the geomorphologic and hydrological characteristics of a river floodplain around 31° 30′ S, are analyzed. The annual dynamics of vegetation was investigated using values of the Normalized Difference Vegetation Index (NDVI) obtained from satellite images at two scales of spatial analysis: the first, at the geomorphologic unit level, through several transects crossing the total width of each unit and, the second, through some transects selected from each unit. Our analysis considered variables of different temporal stability (such as geomorphology, hydrology, vegetation, precipitation, and ground temperature), using scenes corresponding to two hydrological cycles of the system (2009 and 2010), which represented relatively “dry” and “humid” years. Five main geomorphologic units were identified in the floodplain of this anabranching system, which were named considering the predominant landforms and the most important (or typical) water course of each area: Bars and Islands of the Main Channel of the Parana River (BI-MCH), Scroll Bars of the Colastine Branch (SB-C), Scroll Bars of the San Javier River Channel (SB-SJ), Crevasse Splays and Levees of the Malo–Mendieta minor channels (CSL-MM), and Crevasse Splays and Levees of the Santa Fe–Coronda river channels (CSL-SFC). These major units are assembled at different general levels and with variable slopes, which partially control the permanence and other characteristics of the flood flow. The crevasse splays and river levees units were predominantly characterized by herbaceous–bushy marshy vegetation, with low mean NDVI values, while SB-C and BI-MCH units showed two types of forests. The latter showed the highest NDVI values. Unit SB-SJ showed mixed characteristics between the two above-mentioned groups. Mean NDVI values were different among the varying geomorphologic units and during the studied years, showing extreme values of 0.25 and 0.80 after both hydrological cycles. According to our results, the main variations in the seasonal dynamics of vegetation show a higher dependence on the dynamics of the hydrological cycle than on surface temperature or precipitation. The hydrological dynamics of the Parana River floodplain are in turn regulated by its geomorphological architecture, so the annual dynamics of vegetation activity in this system are finally influenced by the geomorphologic unit's level, rather than by the short duration modeling processes (i.e., hydrological cycles or drought–flood pulses).

황강 수생태계에 대한 하천 자연도 평가 연구

I investigated the river morphology and river naturality according to the environment of the Hwang River. The numbers of flexions at the upstream regions were more than those of downstream regions. The Hwang River showed very low overall diversity of the flow. Materials of river shore at low channel width were mainly boulders or gravel at the upstream regions, and the middle and downstream were silts and clay. Artificial masonry and natural materials were mixed from materials of river levees. The Hwang River was some of the natural herbaceous vegetation to riparian zones. Land utilities for floodplain were extremely overall farmland were predominant, and partly used by natural vegetation in the forest, a soccer field, some park facilities, residential, and commercial facilities. The water was width sleep / rivers beam ratio of 10 to 20%. Currently estimation for river naturality widely used in rivers were consisted of a narrow wide a variety of items and did not reflect the actual.

Seismic stability of embankments subjected to pre-deformation due to foundation consolidation

It has been reported that the major cause of earthquake damage to embankments on level ground surfaces is liquefaction of foundation soil. A few case histories, however, suggest that river levees resting on non-liquefiable foundation soil have been severely damaged if the foundation soil is highly compressible, such as thick soft clay and peat deposits. A large number of such river levees were severely damaged by the 2011 off the Pacific coast of Tohoku earthquake. A detailed inspection of the dissected damaged levees revealed that the base of the levees subsided in a bowl shape due to foundation consolidation. The liquefaction of a saturated zone, formed at the embankment base, is considered the prime cause of the damage. The deformation of the levees, due to the foundation consolidation which may have resulted in a reduction in stress and the degradation of soil density, is surmised to have contributed as an underlying mechanism. In this study, a series of centrifuge tests is conducted to experimentally verify the effects of the thickness of the saturated zone in embankments and of the foundation consolidation on the seismic damage to embankments. It is found that the thickness of the saturated zone in embankments and the drainage boundary conditions of the zone have a significant effect on the deformation of the embankments during shaking. For an embankment on a soft clay deposit, horizontal tensile strain as high as 6% was observed at the zone above the embankment base and horizontal stress was approximately half that of the embankment on stiff foundation soil. Crest settlement and the deformation of the embankment during shaking were larger for the embankment subjected to deformation due to foundation consolidation.

하천제방의 비정상 침투해석을 위한 설계홍수파형 산정

본 연구는 제방에 대한 비정상 침투해석에 사용되는 설계홍수파형을 결정하기 위하여 수위자료가 충분히 구축된 우리나라 5대강 수계의 수위관측소 홍수자료를 수집하고 대상 지점의 유역면적, 제방고, 계획홍수량 및 계획홍수위를 조사하였다. 합성홍수파형 결정방법은 일본의 하천제방설계지침에서 제시하고 있는 방법을 보완하여 사용하였다. 합성된 홍수파형의 적용성을 검토하기 위해 합성홍수파형의 감수부 경사와 지속시간을 계획수문곡선과 비교하였고 유역면적에 따른 홍수파형의 감수부 경사와 지속시간의 관계도 분석하였다. 홍수지속시간은 합성홍수파의 홍수지속시간이 계획홍수파의 지속시간보다 크게 산정되었으며, 계획홍수파의 지속시간이 실제 홍수사상의 지속시간을 충분히 대변할 수 없는 것으로 나타났다. 감수부 경사는 대부분의 지점에서 합성홍수파형이 계획홍수파의 감수부 경사보다 완만한 것으로 나타났으며, 유역면적이 넓어질수록 완만해지는 경향을 보였으나, 지속시간과 같이 뚜렷한 상관관계는 보이지 않았다. 하천제방의 비정상 침투해석 시 지속시간은 합성홍수파의 지속시간을 사용하고 감수부 경사는 계획홍수파의 감수부 경사를 사용하는 것이 안전측 설계가 될 것으로 판단된다. 본 연구는 설계홍수수문곡선과 과거대표홍수사상을 이용하여 합성홍수파형을 작성하는 방법을 제안하였으며 5대강 수계 대상지점에 대해 적용하여 그 방법론의 타당성을 확인하였다. Our objective is to compose design flood-hydrograph for analysis of unsteady seepage through river levees. Flood data in the study area, whose observations period are sufficiently long, were collected. Design water surface level and design flood of the study area were analyzed. The method that was introduced in design criteria guideline for river levee in Japan was modified and applied in this study for decision of design flood-hydrograph. For examination of applicability of composed flood-hydrograph, the relation of slope of falling limb and duration of flood-hydrograph was analyzed. It was estimated that flood duration in composed flood-hydrograph was longer than one of design flood-hydrograph, that represents duration of design flood-hydrograph can not take duration of real flood into account. Slope of falling limb of composed flood-hydrograph was more gradual than one of design flood-hydrograph in most study area. Although the results showed that the larger area of a basin accompanies the gentler slope, the pronounced correlation, which can be seen between basin area and flood duration, did not exist. The present study suggests that employing duration of composed flood-hydrograph and slope of falling limb of design flood-hydrograph is safer design when analyzing unsteady seepage through river levees. This study proposed a practical approach to estimate design flood-hydrograph using past flood data. This study applied the methodology to the study area in five river basins and identified the validation.

하천 제방붕괴로 인한 침수재해 위험도 산정기법 개발

제방붕괴로 인한 제내지의 침수 예측은 하천의 흐름, 제방의 붕괴과정 및 제내지의 침수양상을 시간에 따라 변화하는 비정상 해석에 의해 동시에 수행되어야 한다. 그러나 제방붕괴와 관련된 기존의 연구는 범용화된 프로그램을 이용하여 제방 붕괴 해석과정을 시나리오에 의한 선형적 붕괴나 순간적 완전 붕괴로 가정하여 실제 제방붕괴의 비선형성을 제대로 구현할 수가 없었다. 본 연구에서는 이를 지양하고 제방의 토질역학적 이론을 도입하여 제방 안정이론에 기반한 하천 흐름에 의한 제방붕괴과정을 물리학적으로 모형화하고자 하였다. 이러한 제방붕괴 해석모듈의 도입을 통해 하천흐름과 제방붕괴 그리고 제내지의 침수해석이 유기적으로 계산될 수 있는 종합적 제방붕괴 제내지 침수해석 모형으로 구축되도록 하였다. 개발된 모형을 감천 유역에 적용한 결과 하천 부정류 홍수흐름의 경우 제방 붕괴폭의 발달정도에 따라 제내지에서의 침수위, 2 차원 홍수파 전파 양상 및 속도 등이 합리적으로 모의되고 있었다. 본 모형을 보다 실제 제방붕괴 사례의 다양한 적용을 통해 정확성과 실용성이 검증되어진다면 제방붕괴로 인한 제내지 침수해석에 크게 이용될 수 있을 것으로 예상되었고 하천 붕괴 침수예상 및 대처방안 수립에 활용 가능할 것으로 판단되었다. The inundation prediction of protected area due to river levee failure should be carried out simultaneously by unsteady analysis of the time-varying aspects of the flow in the river and the process of the collapse of the levees and inland flooding. However, previous studies associated with levee failure cannot exactly explain actual non-linearity of levee failure, because of using multi-purpose commercial model with assuming instantaneous or linear levee collapse. In this study, the modelling of the process of levee failure by river flow is tried, introducing soil mechanical theory based on levee stability theory. Through the introduction of the levee failure analysis module, inundation analysis, the river flows and levee failure model are organically combined to comprehensive levee failure analysis model. The developed model is applied to Gamcheon and the results shows that in case of river flood, this model simulate reasonably inundation depth on the inland area, 2 dimensional floodwave propagation, breach flow velocity etc. according to aspect of development of breach width. If the accuracy and applicability of this model is improved by the more application to practical cases, the model is expected to effectively analyze levee collapsed flooding and establish action plan against inland inundation.

An evaluation of the stability of Quercus lobata and Populus fremontii on river levees assessed using static winching tests

Tree stability is of great importance not only in forestry, but also in other contexts, such as dam and levee integrity. Extensive damage to New Orleans after levee failures during Hurricane Katrina in 2005 prompted widespread reevaluation of effects of trees and treefalls on the integrity of levees. We undertook a static winching study of western cottonwood (Populus fremontii Wats.) and valley oak (Quercus lobata Nee) trees on levees in the California Central Valley. We hypothesized that Quercus would be stronger; and that the size-stability relationship for both species would be non-linear. We further hypothesized that critical turning moments would decrease with greater soil moisture and with greater sheltering from neighbouring trees. As expected, the critical turning moments increased with tree size and that relationship was non-linear. Size-controlled critical turning moments of Quercus were much greater than Populus, but large inter-site variation made the difference non-significant. While the critical turning moments were not significantly influenced by differences in soil moisture, soil bulk density or soil texture for these sites, significant variation among sites suggest that history or unmeasured components of the environment can exert a strong influence on tree stability. Mirroring trends seen in natural wind disturbances of forests, larger trees were more likely to uproot, while smaller trees exhibited a more even mix of trunk breakage and uprooting. Pulled trees with greater abundance of very close neighbours showed no differences in critical turning moments compared with trees with no nearby (i.e. within 5 m) neighbours. The largest trees had critical turning moments exceeding 1 million newton-meters, demonstrating that large healthy trees in unrestrictive soil conditions can be extremely stable. While the maximum turning moments reported here are above those reported in the literature, when corrected for size, the trees of this study were in the upper range but not beyond turning moments previously reported, suggesting that open-grown trees may not have critical turning moments that greatly exceed those of forest and plantation trees.

RECONNAISSANCE LEVEL STUDY MISSISSIPPI STORM SURGE BARRIER

This paper reports a reconnaissance level study of a storm surge barrier in the Mississippi River. Historical hurricanes have shown storm surge of several meters along the Mississippi River levees up to and upstream of New Orleans. Future changes due to sea level rise and subsidence will further increase the risk of flooding due to hurricane storm surge. A surge barrier downstream of New Orleans has been considered as an alternative to levee raise along the Mississippi River. Hydraulic computations show that the build-up of water behind the barrier due to the Mississippi
 River flow is (much) lower than the hurricane surge protruding up the river in the no-barrier situation. The barrier will probably eliminate the need to upgrade the system upstream of the barrier while providing the same level of hurricane risk reduction. A hybrid barrier (a combination of different gate types) with a primary swing gate for navigation (and flow) and secondary lift gates to accommodate for flow is a technically feasible alternative. The barrier remains open for almost the entire year and would only to be closed during severe tropical events (say once every 2 - 3 years). Several measures are included in the conceptual design to mitigate the navigation impact. The construction costs of the barrier are estimated at $1.6 - 2.6 billion. It is recommended to compare the investment costs of a barrier including adjacent tie-ins to the existing HSDRRS to the costs of upgrading and maintaining the levee system throughout the city of New Orleans.

Numerical Analysis of Liquefaction in a River Levee on Soft Cohesive Ground

During the 2011 off the Pacific coast of Tohoku earthquake, liquefaction at the bottom of embankments extensively damaged river levees in the Tohoku and Kanto areas. This study presents preliminary numerical simulation of liquefaction in a river levee on soft cohesive ground along the Eai River during the earthquake. Static analysis reproduced the initial state of stress and moisture in such an embankment before the earthquake. Static analysis showed a decrease in mean effective stress and an increase in water content at the bottom of the embankment due to the settlement of soft cohesive ground. The effect of initial stress and moisture conditions on the seismic responses of the river levee are discussed through dynamic threephase coupled analysis with an initially deformed configuration and moisture distribution. Numerical results showed that stress relaxation in the embankment caused an increase in settlement at the crest of embankment.

Special Issue on Selected Papers from 9th CUEE

The 9th International Conference on Urban Earthquake Engineering (9th CUEE) and the 4th Asia Conference on Earthquake Engineering (4th ACEE) were jointly held on March 6-8, 2012 in Tokyo, as a part of the research activities of the Center for Urban Earthquake Engineering (CUEE), Tokyo Institute of Technology, Japan. The conference featured state-of-the-art technical presentations on various themes relevant to urban earthquake engineering, followed by special sessions addressing the 11th March 2011 Great East Japan Earthquake and Tsunami that resulted in catastrophic damage and an estimated death toll of 20,000. The conference attracted 465 participants from 31 countries, and disseminated 283 papers. The board members of the Journal of Disaster Research (JDR) decided to publish special issues of JDR, selecting papers from the above joint conference, for the purpose of mainly updating status of Japan’s research/technology. The present issue is on the fields of engineering seismology and geotechnical engineering, including extraordinary ground shaking and liquefactions that affected wide areas during the March 11 incident. Other issues such as those on buildings and infrastructures are also planned. The 8 manuscripts selected and managed by the JDR Guest Editors address the following topics: - Array observations of ground shaking - Large peak ground acceleration and site amplification - Attenuation of the seismic wave - Impact against the water-supply outages - Liquefaction in a river levee on soft cohesive ground - Spread foundation performance affecting superstructure - Performance of piled raft foundation with grid-form ground improvement - Liquefaction of levee body and seepage control The Guest Editors as well as JDR board members thank the authors for their contributions and revisions. They also acknowledge gratefully the reviewers for their invaluable comments on the manuscripts.

The effect of uncertainty on estimates of hurricane surge hazards

It is shown here that uncertainty can significantly affect estimated surge levels over a wide range of annual exceedance probabilities (AEPs). For AEPs in the range of 1 × 10−2–5 × 10−2 in the New Orleans area, estimated surge values with and without consideration of uncertainty differ by about 0.5–1.0 m. Similarly, suppression of natural variability, such as using a single value for Mississippi River discharge in surge simulations, rather than allowing the discharge to vary probabilistically, is shown to produce deviations up to 1 m for the 1 × 10−2 AEP in locations within the mainline river levees in this area. It is also shown that uncertainty can play a critical role in the analysis of very low probability events in the AEP range 1 × 10−4–1 × 10−6. Such events are typically used in designs of structures with major societal impacts. It is shown here that, for this range of AEPs along the west coast of Florida, the neglect of uncertainty can under-predict design surge levels by about 20 % compared to estimated surge levels that include uncertainty.

Liquefaction Consequences and Learned Lessons During the 2011 Mw = 9 Gigantic Earthquake

One of the major impacts caused by the Mw = 9 gigantic earthquake in Japan was subsoil liquefaction in young reclaimed lands. The intensive reconnaissance studies on damage distribution revealed that there was a clear contrast in liquefaction resistance between natural alluvial deposits and younger artificial subsoil. Moreover, liquefaction in originally compacted river levees was recognized. The elongated duration time of ground shaking that was induced by the main shock and strong after shocks probably increased the distortion of geotechnical structures. Liquefaction damage in private properties has led to liability problems. Thus more reliable liquefaction hazard maps are needed. In contrast, a good performance of existing mitigation technologies is noteworthy.

Reconnaissance report on damage in and around river levees caused by the 2011 off the Pacific coast of Tohoku earthquake

The gigantic earthquake on March 11, 2011, caused significant damage in and around river levees over a vast area. Because the amount of damage was on such a huge scale, emergency restoration was difficult and many lessons were learnt. The cause of the damage in most cases was liquefaction either in the foundation or in the levee body, and the latter was recognized as a new technical problem. Many levees in the coastal area experienced the combined effects of the tsunami with the co-seismic subsidence of the earth's crust. Among the many examples of damage, one positive issue was that damage mitigation measures such as drainage and soil improvement were found to be effective. The present text addresses the findings and lessons learnt from the authors' emergency activities after the quake.

Test Study on the CBR of Lime Improved Expansive Soil after Long-Term Immersion

Filled road embankment along river levee or widen river levee as road embankment is often used in highway construction, part of the embankment will always immerged in water for seepage. The intensity of the filler will decrease due to the long-term immersion，which lead to eventually failure, especially in the expansive areas. This paper carried out CBR test on the lime improved expansive soil after different time’s immersion. The test results show: The CBR will linearly decreased with the previous immersion time, and then, it varies very small with the immersion time, and the stable CBR after long term immersion is about 80% of the CBR under standard condition. The paper put forward a prediction model of CBR by the immersion time, it can be used to predict the CBR of improved expansive after long term immersion, and to judge whether it meet the requirements of specification.

Short-Term Sedimentation Processes and Accretion Rates in the Sunchon Bay Estuarine Marsh, South Korea

Park, E.-J.; Yu, K.B.; Ku, C.Y.; Psuty, N.P.; Kim D., and Shin, Y.H., 2012. Short-term sedimentation processes and accretion rates in the Sunchon Bay estuarine marsh, South Korea. Spatial variations in sedimentation during individual tidal cycles were investigated using filter paper traps. The mean mass of sediment deposited in each tidal cycle was higher at the levee edge than at the inner marsh. The mass of sediment decreased with distance from the head of the estuary. There were weak relationships between tidal regime and sediment accumulation. Spatial variations of annual accretion rates were investigated with marker plots. The annual accretion rate at the inner marsh was higher (1.5 to 3.5 cm/y) than that at the tidal river levee edge (0.8 to 3.0 cm/y). Total suspended sediment (TSS) concentrations in the tidal water column indicated that the accretion rate was affected by vegetation. TSS concentrations in the water column leaving the vegetation cover during ebb tidal flows dramatically decreased. There were strong relationships between the concentration of suspended load and accretion rate. The spatial pattern of sedimentation processes at different timescales was mostly due to erosion of the levee edge by tidal flow. The major findings are: (1) The spatial patterns of sedimentation processes at various timescales are different, (2) vertical accretion rates ranged from 0.9 cm/y to 3.5 cm/y, (3) the study area has a depositional regime over the timescale of the present data, (4) the mean and minimum deposition rates in the study area are higher than other cited systems, and (5) the high accretion rate of this area is related to human-induced environmental change, and the sedimentation trajectory is now evolving to a new equilibrium.

Opportunities for the development of tourism in Letea River levee of the Danube Delta biosphere reserve

At the level of the Delta rural areas dominate. The river levee is Letea – C. A. Rosetti locality and it is considered the most isolated settlement in Romania. Making a strategic tool for tourism development in the Rosetti locality from turning its entire natural and cultural heritage has proven to be a multi-step problem, given the economic and social context of human settlements. Lifetime socio-economic development depends on a minimum shipping and road access. The main problem is to change the management of existing resources and to reduce the phenomenon of accentuated depopulation and the current economic underdevelopment. There are many drawbacks, and the last 20 years have brought essential positive changes to the community life. The degree of geographical isolation does not need to be primordial and may diminish its influence by expanding and upgrading communication lines and standard of living by making facilities and utilities, by diversifying local occupations. There are real opportunities for investment to start work and develop rural tourism in this situation.

The Influence of Current on the Height of Wind Wave Run-Up: A comparison of experimental results with the Czech National Standard

The Influence of Current on the Height of Wind Wave Run-Up: A comparison of experimental results with the Czech National StandardOne of the basic questions related to the safety of dikes and river levees is the size of the freeboard. One of the important parameters for freeboard design is the height of waves and wave run-up on levee slopes. Routine and standardised calculations of wave run-up deal with the freeboards of dams where wind waves originate on the still water of the reservoir. In the case of running water in streams (thereinafter only "currents") the effect of wave and current interaction on wave run-up is usually not taken into account due to the lack of reliable knowledge regarding the phenomenon. In the Czech Republic this question is topical in the case of large rivers such as the Elbe, the Vltava and the Morava. Within the framework of the projects Hydralab III and NAZV QI 92A139, hydraulic research and further analysis focused on wave run-up as a result of the combination of current and wind wave parameters were performed. The laboratory research was carried out in a hydraulic flume with a wavemaker on the right bank and a levee with a slope of 1:3 installed on the left bank opposite the wavemaker. Waves were generated both perpendicular and oblique to the levee axis; the angle of oblique wave attack varied within the range of ± 30°. The aim of this paper is to compare the results of the mentioned research with recommendations mentioned in the Czech National Standard CSN 75 0255Calculation of wave effects on water structuresand to quantify the effect of current on the wave run-up height.

Rebuilding Wetlands by Managing the Muddy Mississippi

When spillways were opened to divert the flooding Mississippi last spring, scientists studying the waters sought data that might help restore the river's eroding delta.

Predicting shallow surficial failures in the Mississippi River levee system using airborne hyperspectral imagery

Shallow surficial failures or levee slides in the Mississippi River levee system are very common. There is currently no system to identify or predict the location of these slides before they occur. Studies of slide occurrence mechanisms suggest that probable slide-affected areas are characterized by anomalous vegetation. Compact Airborne Spectrographic Imager II (CASI II) imagery was analysed for selected levee sites in association with slide inventory data and field observations. Normalized Difference Vegetation Index (NDVI), Red edge Vegetation Stress Index (RVSI) and Red Edge Position Index (REP) were calculated from the acquired CASI II imagery. The vegetation indices were used to locate the stressed or anomalous vegetation and predict levee slides. The statistical significance of the predictors was determined by logistic regression. All predictors were found statistically significant for developing a slide prediction model. The slide prediction model was developed by combining the single predictors, categorized vegetation indices, into a model based on all three predictors. Percentage of Search Area Reduction (PSAR) and Failure Index (FI) were used to evaluate the performance of the slide prediction model. Evaluation of the model performance shows that it achieves a maximum FI of 0.43 and PSAR of 99.5.

Natural levees and human settlement in the Song Hong (Red River) delta, northern Vietnam

The Song Hong (Red River) delta, northern Vietnam, is characterized by huge natural levees in an area of the delta plain known as the West Floodplain where fluvial sedimentation predominates. The natural levees along the Day River, a major distributary of the Song Hong, are comparable in size with those of the main course of the Song Hong. The Day River levees are 3–8 km wide and rise 2–5 m above the adjacent backswamps and have played an important role in human settlements since the late Metal age. We discussed the relationships among the natural levees of the Day River, delta progradation and the distribution of archaeological sites on the delta plain. During the early Holocene, the accumulation of sediment discharged by the Song Hong enhanced both aggradation of the floodplain and river mouth progradation within the drowned valley of the Song Hong. Radiocarbon dates from cores, trench exposures, and archaeological sites record a dramatic slowing of aggradation when sea level stabilized during 6–4 cal. kyr BP (the Holocene sea-level highstand). As sea level fell to the present level during 4–0 cal. kyr BP, the river mouth prograded rapidly toward the Gulf of Bac Bo (Gulf of Tonkin) and the river channels extended seaward. In the West Floodplain, lateral accretion overtook vertical accretion to generate the present longitudinal profiles of the Song Hong and Day rivers. During this period, human settlements spread across the backswamp and Holocene terrace area, lagging around 2 kyr behind the shoreline migration.

A comparison analysis of edge-of-field run-off from two sugarcane fields

Agricultural run-off is an important source of nonpoint source pollution. Surface run-off driven by rainfall events was analyzed at two sugarcane fields (SC1 and SC2) in Louisiana, USA. The study site was within a watershed confined by the Mississippi River levee and a drainage canal (St. James Canal). In total, 14 representative rainfall run-off events were analyzed. For comparison with onsite monitoring, a modeling technique was used to estimate run-off. The results show that run-off/rainfall ratios at SC1 were significantly higher (p < 0.0001, n = 14) than at SC2, probably mainly due to a higher sand content of the soil and a higher infiltration rate at SC2 than at SC1. Model-calculated run-off showed substantial overestimation compared with the monitoring results, especially at SC2. Comparison analysis suggests that significant infiltration following precipitation is expected in sandy fields, and water discharge into the groundwater aquifer cannot be ignored. Without considering groundwater discharge in model algorism, the model calculation may significantly overestimate actual surface run-off.