In geography , a confluence (also: conflux ) occurs where two or more watercourses join to form a single channel . A confluence can occur in several configurations: at the point where a tributary joins a larger river ( main stem ); or where two streams meet to become the source of a river of a new name (such as the confluence of the Monongahela and Allegheny rivers, forming the Ohio River ); or where two separated channels of a river (forming a river island ) rejoin at the downstream end. The point of confluence where the channel flows into a larger body of water may be called the river mouth .
47-546: The Marikina River Park is a system of parks, trails, open spaces and recreation facilities along an 11-kilometer (6.8 mi) stretch of the Marikina River in Marikina , eastern Metro Manila , Philippines . The urban riverside park covers an area of 220 hectares (540 acres) running through the villages of Santo Niño, Santa Elena , Jesus de la Peña, San Roque, Calumpang , Barangka and Industrial Valley Complex in
94-630: A confluence is an industrial site, as in Philadelphia or Mannheim . Often a confluence lies in the shared floodplain of the two rivers and nothing is built on it, for example at Manaus , described below. One other way that confluences may be exploited by humans is as sacred places in religions . Rogers suggests that for the ancient peoples of the Iron Age in northwest Europe, watery locations were often sacred, especially sources and confluences. Pre-Christian Slavic peoples chose confluences as
141-433: A gradients, cascades and an adequate junction angle which is sympathetic to the direction of the watercourse’s flow to minimise turbulent flow, maximise evacuation velocity and to ultimately maximise hydraulic efficiency. Since rivers often serve as political boundaries, confluences sometimes demarcate three abutting political entities, such as nations, states, or provinces, forming a tripoint . Various examples are found in
188-520: A large stone outcropping just below water level where the Marikina's children would play, back when the water was still clean, such that this part of the river is still called luksong kabayo . The name of Barangay Tumana refers to the Tagalog word for a wide level land just above water level. The area was considered ideal for vegetable farming due to the rich riversoil, and the annual inundation of
235-500: A number of tributaries in the form of creeks and rivers, and at least one former river-section in Marikina's Barangay Tumana from which the original flow of the river has been diverted. These tributaries drain four municipalities and one city in the province of Rizal, and three cities in the Philippines' National Capital Region. The biggest of these tributaries are upstream in the more mountainous areas of Rodriguez. This includes
282-404: A result, widespread heavy rains impacted regions still recovering from deadly floods triggered by Typhoon Saola less than a week earlier. During a 22‑hour span from August 6–7, 687 millimeters (27.0 in) of rain fell in parts of Metro Manila , leading local media to compare the event to Typhoon Ketsana in 2009, which killed 464 in the city. Some of the most severe flooding took place along
329-580: A strange species of fish has dominated its ecosystem. Since the late 1990s, the Marikina River has been infested by janitor fish . Before, the river was thriving with the local species martiniko , ayungin and biya . The growing fish population has prompted the city government to launch a new program to control their number. The city issued Ordinance 004, series of 2007 , launching the Janitor Fish Eradication Drive in
376-441: A stream contaminated with acid mine drainage combines with a stream with near-neutral pH water; these reactions happen very rapidly and influence the subsequent transport of metals downstream of the mixing zone." A natural phenomenon at confluences that is obvious even to casual observers is a difference in color between the two streams; see images in this article for several examples. According to Lynch, "the color of each river
423-486: A total area of nearly 75.2 hectares (0.752 km ) and is 27 kilometers (17 mi) long. The riverbank has an elevation of 8 meters above sea level at the boundary of San Mateo and Marikina. This slowly falls to an elevation of around 4 meters (13 ft) before the Malanday and Santo Niño boundary. The lowest elevation is along Calumpang which 2 meters (6 ft 7 in) above sea level. The Marikina River has
470-401: A vast assortment of subjects which concern confluences. In hydraulic civil engineering , where two or more underground culverted / artificially buried watercourses intersect, great attention should be paid to the hydrodynamic aspects of the system to ensure the longevity and efficiency of the structure. Engineers have to design these systems whilst considering a list of factors that ensure
517-702: Is a river in eastern Metro Manila , Philippines . It is the largest tributary of the Pasig River , with headwaters located in the Sierra Madre Mountains in Rodriguez , Rizal province. The Marikina River used to be an important transport route during the Spanish colonial era , but its importance as a transport route diminished when the Philippines' national highway system became more established. The resulting lack of river boat traffic and
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#1732776663733564-493: Is believed that blocked pipes, a poorly maintained sewerage system, and uncollected domestic waste were major factors in the speed with which the flood waters engulfed the surrounding area. This prompted President Gloria Macapagal Arroyo to declare a State of National Calamity and set up a task force to rescue the inhabitants. However, the government was forced to admit that resources were in short supply and called for global assistance. Thereafter, efforts have been made to improve
611-494: Is determined by many things: type and amount of vegetation in the watershed, geological properties, dissolved chemicals, sediments and biologic content – usually algae ." Lynch also notes that color differences can persist for miles downstream before they finally blend completely. Hydrodynamic behaviour of flow in a confluence can be divided into six distinct features which are commonly called confluence flow zones (CFZ). These include The broader field of engineering encompasses
658-736: Is drained by Pansol Creek, with headwaters reaching as far up to just behind the University of the Philippines Integrated School campus. Even further south in Barangay Malanday, Marikina, the Lamuan-Bulelak creek also empties into the Marikina River, although its precise mouth area has been blurred by the construction of residential buildings. In Marikina, numerous other creeks flow nearby the Marikina River but are not directly connected. These include
705-424: Is one. The day after, the Marikina River returned in critical level. On September 29, 2011, 5 am, water subsided in the banks of the river and the residents started to clean. At 6 am, water reached 15.2 meters (50 ft). Although located hundreds of kilometers away from the Philippines, the southerly flow from Typhoon Haikui in early August 2012 enhanced the southwest monsoon across much of Luzon . As
752-727: Is the Macapagal Bridge connecting the cities of Quezon and Marikina. Then it crosses over to another administrative border between Quezon City and Pasig with the Manalo Bridge. Further downstream, the remaining bridges prior to the river's southern end are all in Pasig wherein the first three are the Bridgetowne Viaduct (crossing within the Bridgetowne development), Rosario Bridge, and Sandoval Bridge. Then
799-521: Is the San Jose Bridge. Crossing over to the border in between Quezon City and San Mateo, Batasan–San Mateo Bridge crosses the route, and then in Marikina it goes towards four bridges, namely Gil Fernando Bridge, Marikina Bridge, Marcos Bridge , and the Line 2 bridge between Santolan Station to Katipunan Station . The next bridge downstream towards the border between Quezon City and Marikina
846-774: Is used to describe the meeting of tidal or other non-riverine bodies of water, such as two canals or a canal and a lake. A one-mile (1.6 km) portion of the Industrial Canal in New Orleans accommodates the Gulf Intracoastal Waterway and the Mississippi River-Gulf Outlet Canal ; therefore those three waterways are confluent there. The term confluence can also apply to the process of merging or flowing together of other substance. For example, it may refer to
893-729: The Batasang Pambansa Complex in Quezon City . The expressway bridge will be built within the city of Marikina, and will serve as a solution to heavy traffic along the Magsaysay Boulevard-Aurora Boulevard-Marikina-Infanta Highway corridor as well as Ortigas Avenue . The project is expected to commence by 2018. On September 26, 2009, at about 6:00 pm PST, Typhoon Ondoy hit Metro Manila and dumped one month's rainfall in less than 24 hours, causing
940-487: The La Mesa Dam continued to overflow at the time. At least nine people were killed and four others were injured in a landslide in Quezon City . More than fifty people died on this day. This was the worst rain in non-direct typhoon or tropical storm on record that Metro Manila has experienced since 2009, surpassing the accumulated amount of rain brought by Typhoon Ketsana . During the passage of Typhoon Vamco in
987-598: The Pasig River and Marikina River are both biologically dead. In the Pamitinan Protected Landscape located in Sitio Wawa, Brgy. San Rafael, in Rodriguez, the Marikina River is dammed by Wawa Dam , a structure built during the early 1900s to provide water for Manila. From Rodriguez, the river flows through San Mateo then to its namesake city of Marikina . In Pasig , the river meets
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#17327766637331034-614: The deforestation of the upland areas in what is now the Upper Marikina River Basin Protected Landscape contributed to the river's siltation , further reducing its value as a transport route. Due to negligence and industrial development, the river has become very polluted, something that recent Marikina administrations have attempted to address. According to a 2003 pollution report by the Department of Environment and Natural Resources ,
1081-996: The Bankaan Creek in Barangay Parang, the Concepcion Creek in Barangay Concepcion Dos, and the Usiw Creek in Barangay Santa Elena. Instead, these waterways are linked in a complex network with the Balanti, Halang, and Muntingdilao Creeks and the Sapang Baho River , eventually emptying into the Manggahan Floodway and Laguna de Bay . The Marikina River is on the verge of an ecological imbalance as
1128-563: The Marikina River system, including the Manggahan Floodway , to burst its banks rapidly. Along with flooding along other river systems, 80 percent of the National Capital Region became flooded. Also flooded were 25 nearby provinces. In Metro Manila alone, 20 feet (6.1 m) of dirty water forced people to evacuate their homes. By September 30, at least 450,000 inhabitants had been displaced, with at least 380,000 forced into makeshift shelters; 246 people were reported dead. It
1175-416: The Marikina River, which swelled to near-record levels. During the afternoon of August 7, the river reached a height of 20.6 meters (68 ft), well beyond the flood level of 16 meters (52 ft) and about 3 meters (9.8 ft) below the record level set during Typhoon Ketsana. About 70 percent of Metro Manila was affected by flooding. Some areas were submerged in up to 3 meters (9.8 ft). Due to
1222-632: The Marikina River. Only the species disjunctivus was collected from the Pasig River. A total of 18 bridges cross the Marikina. The first bridge from the tri-junction with Boso-Boso and Sapa Bute Rivers is the Pacific Bridge, followed by the Rancho Luisito Way Bridge, Eastwood Greenview Bridge, and Phil Rock Spillway Bridge respectively to the south. Then it goes further towards the first government-owned bridge which
1269-577: The Philippines between November 11 to 12, 2020, the Marikina River surpassed the water levels reached by Typhoon Ketsana in 2009, which brought massive rainfall and caused severe flooding. As of 11:00 PHT the river's water level had risen to 22 meters (72 ft), submerging most parts of the city in flood waters, according to the Marikina Public Information Office. On July 24, 2024, several areas in Luzon were affected by
1316-675: The Tayabasan River and Montalban River, the Boso Boso River, and the Wawa River, which meets the Marikina River just upstream of Wawa Dam . Further downstream from the dam, but still in the town of Rodriguez are the Puray River (which flows near Avilon Zoo ) and Manga River. Until this point the river follows a more or less east–west direction until San Jose, Rodriguez, where it takes a sharp north–south turn towards
1363-550: The annual Mama Mary Fluvial Parade and Festival and the Marikina Christmas Festival. It has an amphitheater, floating stages for cultural events, a Roman Garden, Chinese Pagoda, a gazebo, riverboats and picnic grounds. Sports facilities include a baseball field, a basketball court and a skating rink. A youth camp and a senior citizens lifestyle center can also be found in the park. Marikina River The Marikina River ( Tagalog : Ilog Marikina )
1410-486: The area by the Marikina River during the rainy season, which prevented crawling insect pests from staying permanently. This area was eventually also used for riversoil quarrying and saw an influx of informal settlers which turned it into a residential area, eventually becoming a separate barangay from Concepcion, with Patay na Ilog forming part of the boundary. Further south on the Quezon City side Barangay Pansol
1457-407: The banks of informal settlers and other encroachments, demanding the local industries along the riverbanks to set up water treatment facilities in order improve the river's water quality, planting various flora and building cultural, sports and other historical structures to draw residents back to the river. The Marikina River Park today is a focal point for community and cultural activities. It hosts
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1504-629: The city of Marikina, granting cash incentives to participants, appropriating ₱50,000.00 annually for this purpose. A scientific study of the species found in five locations in the Laguna de Bay tributary system, including the Marikina River, revealed that the specimen of janitor fish previously reported as Hypostomus plecostomus actually belongs to the genus Pterygoplichthys , family Loricariidae . The collected specimens for this study consisted of two species: Pterygoplichthys disjunctivus and Pterygoplichthys pardalis . Both species were collected from
1551-440: The discharge point is structurally stable as the entrance of the lateral culvert into the main structure may compromise the stability of the structure due to the lack of support at the discharge, this often constitutes additional supports in the form of structural bracing. The velocities and hydraulic efficiencies should be meticulously calculated and can be altered by integrating different combinations of geometries, components such
1598-499: The distribution of living organisms (i.e., ecology ) as well; "the general pattern [downstream of confluences] of increasing stream flow and decreasing slopes drives a corresponding shift in habitat characteristics." Another science relevant to the study of confluences is chemistry , because sometimes the mixing of the waters of two streams triggers a chemical reaction, particularly in a polluted stream. The United States Geological Survey gives an example: "chemical changes occur when
1645-412: The drainage system for the whole city by fixing the sewers and the new trademarked "Red Sidewalks". This is the worst storm that Metro Manila has experienced since 1967. On June 24, 2011, heavy rains of Severe Tropical Storm Meari affected Luzon including Metro Manila. The water level in the Marikina River reached its critical level, flooding beside its riverbanks, just near along the river. However,
1692-499: The expanding floods, officials in the city evacuated more than 23,000 residents from flood-prone areas and relocated them to shelters set up across the area. According to a reporter from the British Broadcasting Corporation , many residents were reluctant to leave their belongings behind, and some traveled back through flood waters to retrieve their belongings. Officials feared the flooding could worsen as
1739-479: The flow of Marikina River west, away from the population center of Sitio Bayanbayanan (now known as Concepcion Uno ), where erosion had been a problem. The construction of a levee left behind a remnant waterway now known as Patay na Ilog (literally "Dead River", referring to the former path of the river) where the original path of the river once traversed, which rejoins the Marikina River just south of Tumana Bridge. The dredging for this American era levee left behind
1786-500: The gates of the Manggahan Floodway , a controlled waterway used to prevent flooding in Manila during heavy rains by diverting most of the water of the Marikina toward Laguna de Bay instead of the Pasig River. Located 6.75 kilometers (4.19 mi) downstream is the confluence of the Marikina and Pasig rivers. The river's depth ranges from 3 to 21 meters (9.8 to 68.9 ft) and spans from 70 to 120 meters (230 to 390 ft). It has
1833-446: The heavy rains caused by the strengthening of Typhoon Gaemi and the enhancement of the southwest monsoon. Initial forecasters said that Typhoon Gaemi would not make landfall in the country but moisture from the storm would be drawn into the southwest monsoon and bring heavy rainfall and strong winds to the archipelago. The Marikina River issued its third and highest alarm after it rose to 18.4 meters (60.4 ft). At 14:03 PHT (22:03 UTC) of
1880-558: The list below. A number of major cities, such as Chongqing , St. Louis , and Khartoum , arose at confluences; further examples appear in the list. Within a city, a confluence often forms a visually prominent point, so that confluences are sometimes chosen as the site of prominent public buildings or monuments, as in Koblenz , Lyon , and Winnipeg . Cities also often build parks at confluences, sometimes as projects of municipal improvement, as at Portland and Pittsburgh . In other cases,
1927-638: The municipality of San Mateo , where the Ampid River forms the boundary between Barangays Maly and Ampid. At this point across the river in Quezon City , Calamiong Creek drains Barangay Bagong Silang. Further downstream the Nangka River and its own tributary in the Sapang Labo Creek mark the boundary between San Mateo and Marikina. Somewhere north of Brgy. Tumana in Marikina marks a point at which an American Colonial Era levee shifted
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1974-851: The newest bridge, opened in October 2017, is the Kaginhawaan Bridge that connects barangays Poblacion and Ugong in Pasig. Then the last bridges near the Pasig River confluence are the Vargas Bridge and the Santa Rosa de Lima Bridge. The future expressway bridge is the Metro Manila Skyway . Skyway stage 4 or Metro Manila Expressway/C-6 as planned serves as a connection road from the Stage 3 in Santa Mesa, Manila to
2021-549: The same day, the river increased to 20.6 meters (67.6 ft), which exceeded the limit of 20 meters compared to Typhoon Ketsana of 21.5 meters (70.5 ft) according to Marikina Disaster Risk Reduction and Management Office. Confluence Confluences are studied in a variety of sciences. Hydrology studies the characteristic flow patterns of confluences and how they give rise to patterns of erosion, bars, and scour pools. The water flows and their consequences are often studied with mathematical models . Confluences are relevant to
2068-453: The sites for fortified triangular temples, where they practiced human sacrifice and other sacred rites. In Hinduism , the confluence of two sacred rivers often is a pilgrimage site for ritual bathing. In Pittsburgh, a number of adherents to Mayanism consider their city's confluence to be sacred. Mississippi basin Atlantic watersheds Pacific watersheds Occasionally, "confluence"
2115-686: The water level did not reach its higher banks, into the streets and communities. No casualties were reported but the mud and debris from the river was left by overflowed riverbanks. On September 27, 2011, Typhoon Pedring dumped heavy rains like Ondoy over Luzon including Metro Manila and nearby provinces. Marikina's water level reached a higher level than June 24, 2011, reaching 20.1 meters (66 ft) by 5 pm PHT . The flood submerged houses in several barangays of Marikina and San Mateo. SM City Marikina Basement Parking submerged in muddy water. No deaths were recorded in Marikina, but in San Mateo, there
2162-544: The western part of the city. The park, under development since 1993, is the city's biggest recreational and sports area containing the Riverbanks Center , a mall and office complex, and the biggest roller skating rink in the Philippines. It is a popular area for camping, jogging, biking and other outdoor activities not just for Marikina residents but also for those from nearby cities in Metro Manila. The park
2209-489: Was developed as part of a rehabilitation program called Save the Marikina River Program by the Marikina city government. Launched in 1993, the program aims to reduce flooding and improve the Marikina riverbanks for better water discharge after a 1992 flood left 25% of the city under floodwater. The program involved building access roads to the banks to allow for the cleaning and clearing operations, clearing
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