华南不同类型热带风暴驱动下珠江口表层悬沙分布趋势

本文利用1949—2014年的华南热带风暴数据和1960—2014年珠江入海流量等, 统计分析风暴作用期间珠江口的风强迫和珠江入海水沙强迫特征, 结果表明, 热带风暴对珠江口的风强迫和水沙强迫因台风距珠江口的距离、强度等因素的影响有显著差异。依据水沙及风强迫的强度, 将热带风暴对珠江口的影响简单分成四类: 中风中水沙驱动型、中风高水沙驱动型、强风中水沙驱动型及强风高水沙驱动型。利用MODIS (moderate-resolution imaging spectroradiometer)一级数据和已建立的珠江口表层悬沙指数反演模型, 挑选2002—2010年风暴影响期间无云天气的MODIS影像, 反演珠江口悬沙分布, 分析表层悬沙对四种不同来水来沙及风强迫型风暴的响应特征。结果显示, 中风中水沙型风暴驱动下, 珠江口整体含沙量偏低, 其悬沙扩散及时间变化受控于潮流的强弱; 中风高水沙型风暴驱动下, 八大口门特别是磨刀门浅滩、伶仃洋西滩的含沙量高于其他海域, 其高含沙水体向南偏西方向扩散输运; 强风中水沙风暴驱动下, 河口表层悬沙分布及扩散受主导风向的影响, 在强东北风驱动下, 伶仃洋西侧浅滩含沙量因台风浪的掀沙作用高于湾内大部分海域, 高含沙水体向西南侧扩散; 强风高水沙风暴驱动下珠江河口湾含沙量偏高, 水体一片浑浊, 河口悬沙随偏南风驱动下的沿岸流向东侧输运、扩散。     

Variabilité du panache turbide de la Gironde par télédétection. Effets des facteurs climatiques

The Gironde estuary (France) discharges to the ocean an important amount of suspended particulate matter in the form of turbid plumes. The surface plume is more particularly studied from coastal oceanographic surveys and NOAA/AVHRR satellite data collected during a French programme of coastal oceanography (PNOC-Atlantic). The AVHRR reflectances are atmospherically corrected according to an algorithm based on the clear water concept. The comparison with suspended sediment concentrations are realised by direct and indirect calibrations. The correlations obtained show that at a same concentration the reflectance varies, probably because of varying particle (floc) size and composition. The shape and the surface measured from low resolution (4 km × 4 km) and high resolution (1 km × 1 km) AVHRR data are then compared to the forcings introduced by the fluvial output, the tide, neap and spring tide and the wind variations. The latter have an important effect on the orientation of the distal part of the turbid plume.     

基于遥感分析渤海湾冬季表层悬浮体浓度变化规律

渤海湾是三面环陆的半封闭浅水海湾,海底泥沙悬浮与输运对海洋工程与生态环境有重要影响。冬季是渤海泥沙输运、海床冲刷和海底灾害的主要发生季节,但冬季观测(特别是连续观测)难度大,观测资料相对缺乏,研究冬季悬浮体分布与输运规律对海洋生态环境保护和海洋工程维护等具有指导意义,对认识近海物质及能量循环有重要科学价值。本文基于海洋水色卫星GOCI(Geostationary Ocean Color Imager)遥感影像资料,对渤海湾冬季悬浮体浓度进行了长达8年监测,提取2011—2017年冬季(11、12、1、2月)悬浮体浓度(Total Suspended Sediment, TSS)月平均数据,对渤海湾冬季悬浮体分布情况及输运规律进行研究。结果表明,渤海湾冬季的表层悬浮体浓度分布呈现近岸高离岸低、南岸高北岸低的规律,悬浮体浓度的高值区主要分布于黄河口附近以及渤海湾南岸一带,该海域冬季TSS在80mg/L以上,最高可达200mg/L;海河口及辽东湾沿岸流区域各存在一个低值区,悬浮体浓度介于0—40mg/L。冬季大风天气对水体扰动剧烈,导致渤海湾海底泥沙再悬浮,风速与悬浮体浓度存在正相关性。同时,冬季渤海湾沿岸流等环流增强,使黄河口再悬浮的沉积物向渤海湾西部和北部扩散。     

Horizontal distribution of Changjiang Diluted Water in summer inferred from total suspended sediment in the Yellow Sea and East China Sea

During the summer in the Yellow Sea and East China Sea, the resuspension of the bottom sediment is obstructed by strong stratification and, as a result, the concentration of total suspended sediment (TSS) can be used as an excellent tracer for Changjiang Diluted Water (CDW). To analyze the spatial and temporal variations of the CDW distribution, the monthly mean TSS from Moderate Resolution Imaging Spectroradiometer (MODIS) ocean color data are constructed and are converted to salinity using the relationship between salinity observed from AQUARIUS and TSS. The process produces the detailed horizontal distribution of salinity with very high resolution (1 km). From monthly mean salinity map from 2002 to 2012 in July and August, the expansion patterns of CDW are analyzed. The southerly wind in July and southeasterly wind in August transport the CDW eastward and northeastward, respectively. It is found that the yearly variation of the expansion of CDW toward the southern sea area of Korea is mostly due to the variation of southerly wind and the fluctuations of fresh water discharge into the Changjiang estuary show relatively little impact on the eastward extend of CDW. When 11-year mean (from 2002 to 2012) salinity map in August is compared with World Ocean Atlas 2013, it is revealed that wind in August strengthened six times from 1994 and it causes the expansion of CDW extended 150 km further eastward.     

山东半岛沿岸海域悬浮体时空分布及形成机制分析

依据2015年GOCI(geostationary ocean color imager)卫星影像反演的悬浮体浓度数据,分析了山东半岛沿岸海域表层悬浮体质量浓度和锋面月变化特征,揭示该海域悬浮体的分布特征和扩散格局,并结合风速、波高以及海表温度数据,对其控制因素进行初步探讨。结果显示:研究区内悬浮体质量浓度整体表现为冬季最高,春秋次之,夏季最低的分布特征;悬浮体扩散过程可以划分为4个阶段,冬季稳定外输,春季向岸退缩,夏季近岸贮存,秋季向外扩散。此外,山东半岛近岸存在一条悬浮体质量浓度高于10 mg/L的浑浊带,该浑浊带同样表现出季节变化,它在秋季开始形成,其悬浮体含量、幅宽及延伸范围在冬季达到最大,春季减弱,夏季消失。研究认为山东半岛沿岸海域的表层悬浮体来源主要是海底沉积物的再悬浮。风场、海浪以及沿岸流的强弱变化对悬浮体分布和输运的季节变化有重要的控制作用:风场和海浪影响海水混合搅拌强度,改变海底沉积物再悬浮作用的临界深度,进而影响表层海水悬浮体浓度,致使悬浮体浓度与风浪的月际变化趋势基本一致;沿岸流携带高浓度悬浮体沿山东半岛输运形成沿岸浑浊带,沿岸流的强度变化直接控制浑浊带的季节变化。     

Appraisal of storm beach buffer width for cyclonic waves

The loss of beach sand from berm and dune due to high waves and surge is a universal phenomenon associated with sporadic storm activities. To protect the development in a coastal hazard zone, hard structures or coastal setback have been established in many countries around the world. In this paper, the requirement of a storm beach buffer, being a lesser extent landward comparing with the coastal setback to ensure the safety of infrastructures, is numerically assessed using the SBEACH model for three categories of wave conditions in terms of storm return period, median sand grain size, berm width, and design water level. Two of the key outputs from the numerical calculations, berm retreat and bar formation offshore, are then analysed, as well as beach profile change. After having performed a series of numerical studies on selected large wave tank (LWT) test results with monochromatic waves using SBEACH, we may conclude that: (1) Berm erosion increases and submerged bar develops further offshore as the storm return period increases for beach with a specific sand grain size, or as the sand grain reduces on a beach under the action of identical wave condition; (2) Higher storm waves yield a large bar to form quicker and subsequently cause wave breaking on the bar crest, which can reduce the wave energy and limit the extent of the eroding berm; (3) A larger buffer width is required for a beach comprising small sand grain, in order to effectively absorb storm wave energy; and (4) Empirical relationships can be tentatively proposed to estimate the storm beach buffer width, from the input of wave conditions and sediment grain size. These results would benefit a beach nourishment project for shore protection or design of a recreational beach.     

港湾深槽骤淤的条件探讨

深槽骤淤指深槽底部在特定条件下产生的快速淤积,通常以浮泥形式出现.综合分析杭州湾、三门湾和象山港的地形地貌、水文泥沙及深槽固定剖面风暴前后或大、小潮期间的地形变化得出港湾深槽产生骤淤的基本条件:(1)有丰富的细颗粒物质的供应源;(2)迅速衰减的动力条件;(3)存在明显的负地形.三个条件必须同时得到满足,深槽才能产生骤淤.杭州湾泥沙来源丰富,终年悬沙浓度高,东试挖槽附近受长江冲淡水次级锋面和钱塘江冲淡水锋面影响较大,因此在一个大小潮周期内水动力条件减弱时挖槽处可产生骤淤.三门湾泥沙来源较丰富,正常天气的年份内潮滩处于缓慢淤积状态,而深槽处于冲淤基本平衡状态,但在风暴等灾害性天气下发生强烈的滩、槽泥沙交换,若风暴后处于中小潮汛期则深槽发生骤淤.象山港由于环境隐蔽,水清沙少,沿岸潮滩狭窄,缺少骤淤的物源,即使风暴作用后鹰龙山深槽也没有产生骤淤.     

一个概化的潮汐河口羽状流动力学的初步研究

基于区域陆架海水动力-生态耦合模型(COHERENS)中的三维水动力模型,对一个概化的潮汐河口羽状流动力学进行了初步研究。在均一水深和无风的理想条件下,模拟得到了一个潮周期内概化的潮汐河口表层水体:a)羽状流流场和盐度场的平面分布;b)3种不同河流径流量作用下的羽状流流场和盐度场的平面分布;c)4种不同底床粗糙长度下的羽状流流场和盐度场的平面分布。结果分析表明:a)羽状流的长度在潮汐的作用下递增,而其最大宽度近似呈周期性的变化;b)羽状流的长度和最大宽度都随着河流径流量的增大而分别变长和变宽;c)羽状流的长度和最大宽度都随底床粗糙长度的增大而变小;d)无潮情况下羽状流的凸起明显并存在沿岸流,然而在有潮情况下凸起不明显且无沿岸流;e)水平扩散可能限制了沿岸羽状流的发展。     

Sensitivity study of coastal plumes

INTRODUCTIONIn laboratory, Griffiths and Linden (1981 ) simulated the buoyancy-driven coastal currentsusing both a ring source and a point source in a rotating cylinder tank. The POint source was simifar to the river-forced plume in the coastal region. The coastal plume together with the gravitycoastal current moved along the coast, keeping the barrier on the right in the Northern Hemisphere. Stern et al. (1982) also conducted a similar experiment using a rectangular tank and carried ou…     

Dealing with erosion along the Danube Delta coast. The CONSCIENCE experience towards a sustainable coastline management

The most severe shoreline retreat (over 20 m/year) along the Danube Delta coast has been recorded in the coastal stretch confined by the Sulina branch (north) and Sahalin spit island (south). This erosive trend is caused by the natural evolution of some stretches of the Danube Delta coast, but strongly enhanced by the human activities. Human interventions result in the dramatic decrease in quantity of sediments reaching the coast and in the disruption of natural sediment circulation in the coastal area. EUROSION FP5 Project developed four concepts to be used in coastal studies: coastal sediment cell, coastal resilience, favourable sediment status and strategic sediment reservoir. The main objectives of this study regard the application of the CONSCIENCE methodology and test of the concepts in order to identify and understand the main threats for Sulina - Sahalin littoral cell, especially the coastal erosion one, as well as to provide a sound working methodology for coastal managers to deal with these threats. The sediment budget computed in previous studies, as well as the field observations, indicate a lack of sediments for the littoral cell (unfavourable sediment status). In order to asses the vulnerability of the coast to short term extreme events (especially storms), simulations of water level changes were performed and calibrated with the field observations. A processes based numerical model was used to simulate the storm induced water level variations and the main input data were the bathymetry of the active beach, wind direction and speed (storm scenarios) and the characteristics of water and air. The results show large water level increases for the central part of the study zone, especially for northern wind directions.The main solution proposed to deal the problems arising from a sediment-starved coast, vulnerable to the extreme events, is artificial nourishment. Two strategic sediment reservoirs were identified, both of them at the northern boundary of the cell: the sediments dredged periodically from Sulina mouth and the sediments accumulated in Musura Bay, just north of Sulina jetties. The transfer of these sediments towards the central part of the littoral cell Sulina - Sahalin would decrease the erosion rates to a natural level and restore the natural coastal resilience. The methodology developed in CONSCIENCE Framework and applied to Danube Delta coastal zone provided good results when problems and solutions for the coastal zone were to be identified and tested. This methodology and its related results can be applied by the local coastal managers to Sulina - Sahalin littoral cell, while this experience can be extended to other similar environments facing the same problems.     

Prediction of shoreline behaviour for Madras, India-a numerical approach

A satellite port has been proposed about 14.8 km north of Madras port on the east coast of India. As the interference of a satellite port with the existing pattern of longshore sediment transport will generate coastal imbalance in the region, a numerical model study involving sediment transport and combined wave refraction-diffraction was conducted to predict the shoreline behaviour. A realistic approach to the study was made to meet the objectives by considering wave height-wave period distributions in the region and duration and sequence of their occurrence during major monsoon seasons. This method of analysis enabled us to predict: (i) the extent of general shoreline advancement, particularly in front of a tidal inlet—a source of the cooling water requirement for an existing thermal power plant; (ii) the extent of the coastal region that will be affected owing to recession of shoreline and its impact on: (a) the fishing community living along the coastal stretch; (b) the national highway running along the coast; and (c) the changes in nearshore bathymetry. Based on the studies, management plans were drawn to safeguard the coastal region from imbalances that will arise out of construction of the satellite port. This paper highlights the effects of a satellite port on the coastal region and the need for proper management.     

Variations of suspended sediment transport caused by changes in shoreline and bathymetry in the Zhujiang (Pearl) River Estuary in the wet season

A wave-current-sediment coupled numerical model is employed to study the responses of suspended sediment transport in the wet season to changes in shoreline and bathymetry in the Zhujiang (Pearl) River Estuary (ZRE) from 1971 to 2012. It is shown that, during the wavy period, the large wave-induced bottom stress enhances sediment resuspension, resulting in an increase in the area of suspended sediment concentration (SSC) greater than 100 mg/L by 183.4%. On one hand, in spring tide, the change in shoreline reduces the area of SSC greater than 100 mg/L by 17.8% in the west shoal (WS) but increases the SSC, owing to the closer sediment source to the offshore and the stronger residual current at the Hengmeng (HEM) and Hongqili (HQL) outlets. The eastward Eulerian transport is enhanced in the WS and west channel (WC), resulting in a higher SSC there. The reclamation of Longxue Island (LXI) increases SSC on its east side and east shoal (ES) but decreases the SSC on its west and south sides. Moreover, in the WC, the estuarine turbidity maximum (ETM) is located near the saltwater wedge and moves southward, which is caused by the southward movement of the maximum longitudinal Eulerian transport. In neap tide, the changes are similar but relatively weaker. On the other hand, in spring tide, the change in bathymetry makes the SSC in the WS increase, and the area of SSC greater than 100 mg/L increases by 11.4% and expands eastward and southward, which is caused by the increases in wave-induced bottom stress and eastward Eulerian transport. On the east side of the WC, the eastward Eulerian transport decreases significantly, resulting in a smaller SSC in the middle shoal (MS). In addition, in the WC, the maximum SSC is reduced, which is caused by the smaller wave-induced bottom stress and a significant increase of 109.88% in southward Eulerian transport. The results in neap tide are similar to those in spring tide but with smaller changes, and the sediment transports northward in the WC owing to the northward Eulerian transport and vertical shear transport. This study may provide some references for marine ecological environment security and coastal management in the ZRE and other estuaries worldwide affected by strong human interventions.     

辽东湾两侧砂质海岸侵蚀灾害与防治

自20世纪60年代至90年代，由于多种原因，辽东湾东西两侧的初始沙质海岸侵蚀范围逐年扩大，侵蚀不断加剧，给当人民的生产和生活带来严重危害。由多年监测资料发现，侵蚀严重的熊岳岸线以2～4m／a的速率而大幅度后退，特别严重的地区最大后退达10km；辽西绥中某些岸段平均每年后退1～2m。20世纪90年代后期，由于一些海域管理措施的出台和相应的海岸防护工程的建设，海岸侵蚀逐渐减弱。通过现场调查和多年监测，分析了辽东湾东西两侧砂质海岸侵蚀的特点，认为海岸组成物质松散与海岸动力作用强烈是本区现代海岸侵蚀的基本条件，人为活动是关键因素，并提出了海岸侵蚀灾害的防治对策。     

海岸侵蚀作用下海岸带地区极端风暴洪水风险评估 —以上海石化为例

海堤是海岸带地区社会经济活动的重要保护屏障。海岸侵蚀的加剧将导致海堤稳定性和安全性降低, 增加海岸带地 区遭受极端风暴洪水的风险, 进而影响到海岸带地区的安全。本文选择上海石化这一遭受海岸侵蚀较为严重的区域作为研究 区, 利用 GIS 分析了 1972—2020 年近岸海床侵蚀特征, 并基于 2000—2020 年-5 m 等深线变化评估了上海石化近岸海堤的 稳定性。结果表明： 1972—2020 年间上海石化前沿海床整体以侵蚀为主, 石化近岸东侧以及西侧局部的浅滩侵蚀明显, 城 市沙滩中段、第 6 次围堤处以及码头东岸海堤稳定性最低。基于上述研究结果, 考虑海堤稳定性薄弱段出现极端风暴洪水漫 堤或溃堤情景, 模拟并分析了上海石化 2010 年 、2030 年和2050 年遭受千年一遇极端风暴洪水的风险。结果显示： 在 2010 年基准年情景下, 受海岸侵蚀作用最明显的城市沙滩和第6 次围堤区域遭遇极端风暴洪水的风险最高, 到 2050 年, 当前稳 定性较好的海堤安全性也将大大降低, 与 2010 年相比, 上海石化近岸地区的直接经济损失将会增加近 3 倍。     

Impacts of stormwater discharges on the nearshore benthic environment of Santa Monica Bay

Although large loads of potentially toxic constituents are discharged from coastal urban watersheds, very little is known about the fates and eventual impacts of these stormwater inputs once they enter the ocean. The goal of this study was to examine the effects of stormwater discharges on the benthic marine environment of Santa Monica Bay. Sediment samples were collected across a gradient of stormwater impact following significantly sized storm events offshore Ballona Creek (a predominantly developed watershed) and Malibu Creek (a predominantly undeveloped watershed). Sediments offshore Malibu Creek had a greater proportion of fine-grained sediments, organic carbon, and naturally occurring metals (i.e., aluminum and iron), whereas sediments offshore Ballona Creek had higher concentrations of anthropogenic metals (i.e., lead) and organic pollutants (i.e., total DDT, total PCB, total PAH). The accumulation of anthropogenic sediment contaminants offshore Ballona Creek was evident up to 2 km downcoast and 4 km upcoast from the creek mouth and sediment concentrations covaried with distance from the discharge. Although changes in sediment texture, organic content, and an increase in sediment contamination were observed, there was little or no alteration to the benthic communities offshore either Ballona or Malibu Creek. Both sites were characterized as having an abundance, species richness, biodiversity and benthic response index similar to shallow water areas distant from creek mouths throughout the Southern California Bight. There was not a preponderance of pollution tolerant, nor a lack or pollution sensitive, species offshore either creek mouth.     

Quantifying the impact of watershed urbanization on a coral reef: Maunalua Bay,Hawaii

Human activities in the watersheds surrounding Maunalua Bay, Oahu, Hawaii, have lead to the degradation of coastal coral reefs affecting populations of marine organisms of ecological, economic and cultural value. Urbanization, stream channelization, breaching of a peninsula, seawalls, and dredging on the east side of the bay have resulted in increased volumes and residence time of polluted runoff waters, eutrophication, trapping of terrigenous sediments, and the formation of a permanent nepheloid layer. The ecosystem collapse on the east side of the bay and the prevailing westward longshore current have resulted in the collapse of the coral and coralline algae population on the west side of the bay. In turn this has lead to a decrease in carbonate sediment production through bio-erosion as well as a disintegration of the dead coral and coralline algae, leading to sediment starvation and increased wave breaking on the coast and thus increased coastal erosion. The field data and resulting coral reef ecohydrology model presented in this paper demonstrate and quantify the importance of biophysical processes leading to coral reef degradation as the result of urbanization. Coral restoration in Maunalua Bay will require an integrated ecosystem approach.     

Stormwater plume detection by MODIS imagery in the southern California coastal ocean

Stormwater plumes in the southern California coastal ocean were detected by MODIS-Aqua satellite imagery and compared to ship-based data on surface salinity and fecal indicator bacterial (FIB) counts collected during the Bight'03 Regional Water Quality Program surveys in February–March of 2004 and 2005. MODIS imagery was processed using a combined near-infrared/shortwave-infrared (NIR-SWIR) atmospheric correction method, which substantially improved normalized water-leaving radiation (nLw) optical spectra in coastal waters with high turbidity. Plumes were detected using a minimum-distance supervised classification method based on nLw spectra averaged within the training areas, defined as circular zones of 1.5–5.0-km radii around field stations with a surface salinity of S < 32.0 (“plume”) and S > 33.0 (“ocean”). The plume optical signatures (i.e., the nLw differences between “plume” and “ocean”) were most evident during the first 2 days after the rainstorms. To assess the accuracy of plume detection, stations were classified into “plume” and “ocean” using two criteria: (1) “plume” included the stations with salinity below a certain threshold estimated from the maximum accuracy of plume detection; and (2) FIB counts in “plume” exceeded the California State Water Board standards. The salinity threshold between “plume” and “ocean” was estimated as 32.2. The total accuracy of plume detection in terms of surface salinity was not high (68% on average), seemingly because of imperfect correlation between plume salinity and ocean color. The accuracy of plume detection in terms of FIB exceedances was even lower (64% on average), resulting from low correlation between ocean color and bacterial contamination. Nevertheless, satellite imagery was shown to be a useful tool for the estimation of the extent of potentially polluted plumes, which was hardly achievable by direct sampling methods (in particular, because the grids of ship-based stations covered only small parts of the plumes detected via synoptic MODIS imagery). In most southern California coastal areas, the zones of bacterial contamination were much smaller than the areas of turbid plumes; an exception was the plume of the Tijuana River, where the zone of bacterial contamination was comparable with the zone of plume detected by ocean color.     

2003年广东风暴潮分析和预报总结

2003年登陆广东的3个台风(0307号伊布都、0312号科罗旺、0313号杜鹃),中心气压及风力都十分强,分别造成全省沿海较高的风暴潮位,甚至部分沿海破了或平了历史记录。3个强台风同一年登陆广东且分别造成珠江口、粤西、粤东较严重风暴潮的情况十分罕见。本文从台风特性、台风增水、台风风暴高潮位、重现期等方面进行分析,并从中分别总结出我省沿海各岸段台风风暴潮的主要特点及作业预报经验。     

The ages of the storm beaches of the Lakshadweep (Laccadives)

Most of the islands in the Lakshadweep are marked by storm beaches on the eastern seaward shores and sandy beaches on the western lagoonal shores. The storm beaches consist of up to 3–4 sets almost at the same level and extend up to a distance of 5–12 km on some of the islands. They largely comprise uncemented pebbles, shingles, cobbles and boulders. The tracks for cyclones (1891–1960) show that the islands are normally hit by post-monsoon (November) cyclones from the east. The waves generated by these cyclones have formed the storm beaches. Radiocarbon dates of the storm beaches range from modern to 2975 ± 100 BP and indicate clustering between 3000 to 2000 BP and present to 500 BP. The younger storm beaches towards the shore suggest that parts of the islands have grown by about 30 m in the last 2780 years (Chetlat), 120 m in 1620 years (Kiltan) and even 100 m in 470 years (Minicoy). The absence of the storm beaches on some of the islands, younger beaches towards the shore and the clustering of ages, and the lack of lateral and chronological continuity may be explained by periodic stormy conditions rather than by the changes in the sea level. The number of storms in the Arabian Sea has varied from a minimum of 1 in 1949 to 10 in 1893, 1926 and 1930. It is very likely that such changes would have occurred in the past also.     

Dispersal forcing of southern California river plumes,based on field and remote sensing observations

River plumes are important pathways of terrestrial materials entering the sea. In southern California, rivers are known to be the dominant source of littoral, shelf and basin sediment and coastal pollution, although a basic understanding of the dynamics of these river inputs does not exist. Here we evaluate forcing parameters of a southern California river plume using ship-based hydrographic surveys and satellite remote sensing measurements to provide the first insights of river dispersal dynamics in southern California. Our results suggest that plumes of the Santa Clara River are strongly influenced by river inertia, producing jet-like structures ~10 km offshore during annual recurrence (~two-year) flood events and ~30 km during exceptional (~10-year recurrence) floods. Upwelling-favorable winds may be strong following stormwater events and can alter dispersal pathways of these plumes. Due to similar runoff relationships and other reported satellite observations, we hypothesize that interia-dominated dispersal may be an important characteristic of the small, mountainous rivers throughout southern California.