TOWARDS AN INTEGRATED MANAGEMENT OF THE LOWER GRIJALVA RIVER (MEXICO)!

Transcription

1 TOWARDS AN INTEGRATED MANAGEMENT OF THE LOWER GRIJALVA RIVER (MEXICO)! First phase:! Controlling the flow and sediment discharge distribution at the bifurcation between the Samaria and Carrizal rivers! HYDREUROPE

2 HYDREUROPE CHIAPAS

3 What is the problem?! The recurrent inundations in Villahermosa (last ones in 1999 & 2007) require an urgent solution!! After the 1999 flood event, the authorities decided to:!! Construct a weir in the rio Carrizal!! Investigate effective (definitive?) solutions to control the inundations!! Nonetheless, the scheme should be designed taking into account the potamological context (potamology = science of rivers, more general than fluvial hydraulics)! HYDREUROPE

4 GRIJALVA USUMACINTA RIVER BASINS Average annual runoff in Mm 3 Río Grijalva 36, % Río Usumacinta 62, % Total 98, Basin Río Grijalva Basin Río Usumacinta Areas in km 2 Río/País México Guatemala Total por Ríos Grijalva 52, , , Usumacinta 30, , , Total por paises 82, , , Total de totales HYDREUROPE

5 Potamological context! The Grijalva river has the largest part of its basin in the Sierra Madre and enters its lower reach in the large coastal plain, before discharging in the Golf of Mexico!! The last stretch is within an alluvial fan (delta) in which several branches have developed through time by avulsion (change of the river course)! HYDREUROPE

6 BARRA DE SAN PEDRO BARRA DE SAN PEDRO BARRA DE SAN PEDRO BARRA DE FRONTERA BARRA DE FRONTERA BARRA DE FRONTERA BARRA DE TUPILCO BARRA DE DOS BOCAS BARRA DE CHILTEPEC Sta. Ma. de la Victoria FRONTERA BARRA DE TUPILCO BARRA DE DOS BOCAS BARRA DE CHILTEPEC FRONTERA BARRA DE TUPILCO BARRA DE DOS BOCAS BARRA DE CHILTEPEC FRONTERA PARAISO COMALCALCO NACAJUCA JALPA CUNDUACAN R i o M e z c a l a p a CARDENAS VILLAHERMOSA ( San Juan Bautista ) Rio de la Sierra Rio G r i j a l v a PARAISO COMALCALCO R i o S e c o CUNDUACAN CARDENAS R i o JALPA NACAJUCA VILLAHERMOSA ( San Juan Bautista ) Rio de la Sierra Rio G r i j a l v a CARDENAS PARAISO COMALCALCO R i o S e c o CUNDUACAN R i o M e z c a l a p a JALPA Rio Carrizal NACAJUCA Rio de la Sierra Rio G r i j a l v a VILLAHERMOSA ( San Juan Bautista ) HUIMANGUILLO HUIMANGUILLO M e z c a l a p a o Rio Viejo ROMPIDO DE NUEVA ZELANDIA HUIMANGUILLO o Rio Viejo PICHUCALCO Rio Teapa TACOTALPA TEAPA SIGLO XVI Rio Tacotalpa R i o M e z c a l a p a PICHUCALCO Rio Teapa TACOTALPA TEAPA Rio Tacotalpa ROMPIDO DE NUEVA ZELANDIA R i o M e z c a l a p a ROMPIDO MANGA DE CLAVO PICHUCALCO Rio Teapa TACOTALPA TEAPA Rio Tacotalpa ROMPIDO MANGA DE CLAVO BARRA DE SAN PEDRO BARRA DE SAN PEDRO BARRA DE SAN PEDRO BARRA DE FRONTERA BARRA DE FRONTERA BARRA DE FRONTERA BARRA DE TUPILCO BARRA DE DOS BOCAS PARAISO COMALCALCO R i o S e c o CUNDUACAN CARDENAS BARRA DE CHILTEPEC JALPA NACAJUCA Rio Carrizal Rio Gonzalez Rio G r i j a l v a VILLAHERMOSA ( San Juan Bautista ) FRONTERA BARRA DE TUPILCO BARRA DE DOS BOCAS BARRA DE CHILTEPEC PARAISO COMALCALCO R i o S e c o CUNDUACAN CARDENAS Rio Cuxcuachapa JALPA NACAJUCA Rio Carrizal Rio Jalupa Rio Cañas VILLAHERMOSA ( San Juan Bautista ) Rio G r i j a l v a FRONTERA BARRA DE TUPILCO CARDENAS BARRA DE DOS BOCAS PARAISO COMALCALCO R i o S e c o Rio Cuxcuachapa JALPA CUNDUACAN Rio Samaria Rio Carrizal BARRA DE CHILTEPEC NACAJUCA Rio Medellin Rio G r i j a l v a Rio Chilapilla VILLAHERMOSA ( San Juan Bautista ) FRONTERA Rio Chilapa R i o Rio Viejo Rio de la Sierra M e z c a l a p a o Rio Viejo Rio de la Sierra Rio Viejo Rio de la Sierra HUIMANGUILLO R i o M e z c a l a p a ROMPIDO DE LA PIGUA Rio Teapa TACOTALPA Rio Tacotalpa TEAPA PICHUCALCO ROMPIDO DE LA PIGUA HUIMANGUILLO R i o M e z c a l a p a ROMPIDO DE CAÑAS Rio Teapa TACOTALPA TEAPA ROMPIDO PICHUCALCO DE CAÑAS 1940 Rio Tacotalpa HUIMANGUILLO R i o M e z c a l a p a ROMPIDO DEL VELADERO ABIERTO EN 1952 CERRADO EN 1953 PICHUCALCO Rio Teapa TACOTALPA TEAPA Rio Tacotalpa ROMPIDO DEL VELADERO HYDREUROPE

7 Summary BARRA DE SAN PEDRO BARRA DE FRONTERA BARRA DE TUPILCO CARDENAS BARRA DE DOS BOCAS PARAISO COMALCALCO R i o S e c o Rio Cuxcuachapa JALPA CUNDUACAN Rio Samaria Rio Carrizal BARRA DE CHILTEPEC NACAJUCA Rio Medellin Rio G r i j a l v a Rio Chilapilla VILLAHERMOSA ( San Juan Bautista ) FRONTERA Rio Chilapa Rio de la Sierra Rio Viejo HUIMANGUILLO R i o M e z c a l a p a ROMPIDO DEL VELADERO ABIERTO EN 1952 CERRADO EN 1953 PICHUCALCO Rio Teapa TACOTALPA TEAPA Rio Tacotalpa HYDREUROPE

8 HYDREUROPE Formation of a delta, meaning reduction of slopes in the lower reach

9 Rio Seco (ancient course) Present course Usumacinta HYDREUROPE

10 HYDREUROPE

11 Coastal plain 4 dams built from 1964 till 1987 for hydropower production and flood flow regulation Mountains HYDREUROPE

12 SCHEME OF DAMS ON THE RÍO GRIJALVA Profile of the río Grijalva The rio Grijalva runoff, during floods, were much larger before the construction of the dams. In 1963, discharges over m 3 /s were observed at the hydrometric station of Peñitas. (msnm) HYDREUROPE

13 CAPACITY (In millions cubic meters) (For flood regulation) SCHEME OF DAMS ON THE RÍO GRIJALVA 14,000 3,460 (msnm) The Malpaso dam was built to regulate the flood events MALPASO (1964) * ** HYDREUROPE

14 CAPACITY (In millions cubic meters) (For flood regulation) SCHEME OF DAMS ON THE RÍO GRIJALVA 14,000 3,460 MALPASO Discharges reduced with regulation La presa by Malpaso the reservoir, nonetheless, construyó con operation la of spillway finalidad was de needed regular in las 1969, 1970 avenidas. y 1973, before construction of Angostura. (msnm) MALPASO (1964) * ** HYDREUROPE

15 CAPACITY (In millions cubic meters) 20,000 (For flood regulation) 8,500 ANGOSTURA (1975) 539.5* 533.0** ANGOSTURA SCHEME OF DAMS ON THE RÍO GRIJALVA 14,000 3,460 Is the reservoir with the largest regulation capacity of Mexico. (msnm) MALPASO (1964) * ** HYDREUROPE

16 CAPACITY (In millions cubic meters) 20,000 (For flood regulation) 8,500 ANGOSTURA (1975) 539.5* 533.0** CHICOASÉN SCHEME OF DAMS ON THE RÍO GRIJALVA 1, CHICOASÉN (1980) 395.0* 392.5** 14,000 3,460 Hydropower scheme with highest potential of MW, but with little effect on flow regulation. MALPASO (1964) (msnm) * ** HYDREUROPE

17 CAPACITY (In millions cubic meters) 20,000 (For flood regulation) 8,500 ANGOSTURA (1975) 539.5* 533.0** SCHEME OF DAMS ON THE RÍO GRIJALVA 1, CHICOASÉN (1980) 395.0* 392.5** 14,000 3,460 MALPASO (1964) 1,485 1,091 In December 1967, in the Ostuacan river, between Malpaso and Peñitas, was observed a flood event with discharge of over m 3 /s. (msnm) * ** PEÑITAS (1987) 200 HYDREUROPE * 87.4** 100

18 Impact of the dams! The 4 dams constructed between 1964 and 1987 had a significant impact on the hydrological regimen of the Mezcalapa river (Grijalva downstream of Peñitas)!! Natural flood events disappeared and the operation of Peñitas dam determines the discharges (little contribution of Platanar river)!! A compensation dam foreseen to avoid rapid discharge fluctuation during the day has not yet been constructed! HYDREUROPE

19 MONTHLY GASTOS DISCHARGES MENSUALES IN PENITAS PENITAS ,000 9,000 Mal Paso Angostura Chicoasén Peñitas 8,000 7,000 DISCHARGES (M3/S) GASTOS (M3/S) 6,000 5,000 4,000 3,000 2,000 1,000 0 Ene-47 Ene-51 Ene-55 Ene-59 Ene-63 Ene-67 Ene-71 Ene-75 Ene-79 Ene-83 Ene-87 Ene-91 Ene-95 Ene-99 DATES (MONTHS) FECHA (MESES) MÁXIMO MÍNIMO MEDIO HYDREUROPE

20 GRIJALVA AVENIDAS FLOOD DEL EVENTS GRIJALVA BEFORE ANTES AND AFTER Y DESPUES CONSTRUCTION DE CONSTRUIR OF PENITAS PENITAS DAM 10,000 9,000 8,000 GASTO LIQUIDO (M3/S) DISCHARGES (M3/S) 7,000 6,000 5,000 4,000 3,000 2,000 1,000 AFTER DESPUES COMPLETION DE CONSTRUIR OF LAST DAM PENITAS (PENITAS) 0 1/Sep 11/Sep 21/Sep 1/Oct 11/Oct 21/Oct 31/Oct 10/Nov 20/Nov 30/Nov DATES (MONTHS) FECHAS (D-M) HYDREUROPE

21 Hydrological impact of the dams! Change in hydrological regimen, dry and flood seasons in quite constant monthly discharges, except in flood event periods!! Between 1987 and 1999, operation of Peñitas dam produced discharge fluctuations during the day between a very low and a very high value (depending on the electricity demand)! HYDREUROPE

22 HYDROGRAM 1987, THE YEAR Hidrograma AFTER CONSTRUCTION Peñitas 1987 OF PENITAS DAM 6,000 5,500 5,000 4,500 4,000 Gastos (m3/s) 3,500 3,000 2,500 DISCHARGES (M3/S) 2,000 1,500 1, /01/ /01/ /01/ /02/ /02/ /03/ /03/ /04/ /04/ /05/ /05/ /06/ /06/ /07/ /07/ /07/ /08/ /08/ /09/ /09/ /10/ /10/ /11/ /11/ /12/ /12/ /12/1988 Fechas (días) DATES (DAYS) HYDREUROPE

23 HYDROGRAM VARIACION IN OCTOBER DEL 1987, GASTO THE YEAR LIQUIDO AFTER EN CONSTRUCTION OCTUBRE DE OF 1987 PENITAS DAM 2,000 1,500 GASTO LIQUIDO (M3/S) DISCHARGES (M3/S) 1, Oct 02-Oct HYDREUROPE Oct 04-Oct 05-Oct 06-Oct 07-Oct 08-Oct 09-Oct 10-Oct 11-Oct 12-Oct 13-Oct 14-Oct 15-Oct 16-Oct 17-Oct DIAS DATES (DAYS) Gasto Medio Gasto Mínimo Gasto Máximo 18-Oct 19-Oct 20-Oct 21-Oct 22-Oct 23-Oct 24-Oct 25-Oct 26-Oct 27-Oct 28-Oct 29-Oct 30-Oct 31-Oct

24 Sedimentological impact of the dams! Sedimentation in the dam reservoirs produce a deficit in sediment supply to the Lower Grijalva!! Only the Platanar river carries sediment to the Mezcalapa river, with large quantities of material from the Chichonal volcano eruption (1982), in total 9 millions cubic meters ashes! HYDREUROPE

25 The river response to the dams! By sediment deficit, clear water has the tendency to erode the riverbed downstream of Peñitas dam (impact controlled by the nature of the riverbed: rocs)!! The water level gauging station just downstream of the dam hangs today above the waterlevel (was already replaced twice to follow the descent of the riverbed, degradation explained by Lane Balance)!! Products of this erosion move in downstream direction to deposit further, creating many and large sand- and gravel bars in the Mezcalapa! HYDREUROPE

26 HYDREUROPE

27 HYDREUROPE

28 Río Mezcalapa in Huimanguillo, Puente Solidaridad Bank protection structures HYDREUROPE

29 The river response to the dams! A meandering river course would be more adequate to the new hydrological regimen!! The strong discharge fluctuation, in the presence of the large sand and gravel bancs, produced between 1987 y 1999 flow deviations towards the banks,!!!! what induced always more erosions, causing a braided riverbed in the lower part of the Mezcalapa! HYDREUROPE

30 HYDREUROPE

31 The bifurcation of the Mezcalapa river! The bifurcation of the Mezcalapa in Samaria and Carrizal rivers exists since 1940, when occurred the Cañas avulsion!! Information is missing on the development of the river between 1940 and 1964, when started construction of the dams!! However, aerial photographs reveal the tendency in the Mezcalapa to amplify its course, although not as much as in the Carrizal river! HYDREUROPE

32 HYDREUROPE

33 HYDREUROPE

34 1996 HYDREUROPE

35 2000 Samaria meandering (canaliform) Samaria braided HYDREUROPE

36 HYDREUROPE

37 The bifurcation of the Mezcalapa river! Impact of Samaria bridges:!! Produce backwater, with effect on sedimentation when flood retreats!! Tendency to outflank by bank erosion!! The operation of the dams results in strong and rapid daily fluctuations of discharges!! The power of the flow is distributed in a too wide riverbed, reducing the sediment transport capacity!! A sediment gauging campaign was started with a WMO funded project! HYDREUROPE

38 US DHS-59 for suspended load transport HYDREUROPE

39 US BL-84 for bedload transport HYDREUROPE

40 US BL-84 for bedload transport Operated from a small unit HYDREUROPE

41 Delft Bottle BD2 for near-bed load transport Operated from a small unit HYDREUROPE

42 Delft Bottle BD1 for suspended load transport Fitting the tail; operated from a small unit HYDREUROPE

43 8,000 Flow and sediment transport relationship Mezcalapa! Relación gasto sólido (arena y grava) con el gasto líquido Mezcalapa 7,000 6,000 Gasto sólido (m3/día) 5,000 4,000 3,000 y = e x y = e x BL-84 BD2 BD1 Expon. (BD1) Expon. (BD2) Expon. (BL-84) 2,000 y = e x 1, ,000 1,200 1,400 1,600 Gasto líquido (m3/s) Sediment transport: BL-84 = bed-load; Delft bottle BD2= near-bed; Delft bottle BD1= suspension HYDREUROPE

44 20,000 Flow and sediment transport relationship Mezcalapa! Relación gasto sólido (arena y grava) con el gasto líquido Mezcalapa 18,000 Gasto sólido (cumulativo, m3/día) 16,000 14,000 12,000 10,000 8,000 6,000 4,000 2,000 0 y = e x BD1 y = e 0.002x BD2 84 y = e x ,000 1,200 1,400 1,600 Gasto líquido (m3/s) BL-84 BL-84 + BD2 BL-84 + BD2 + BD1 Expon. (BL-84 + BD2 + BD1) Expon. (BL-84 + BD2) Expon. (BL-84) Sediment transport: BL-84 = bed-load; Delft bottle BD2= near-bed; Delft bottle BD1= suspension HYDREUROPE

45 Flow - sediment transport relationship 20,000 Relación gasto sólido (arena y grava) con el gasto líquido Mezcalapa 20,000 Relación gasto sólido (arena y grava) con el gasto líquido Mezcalapa 18,000 18,000 16,000 16,000 Gasto sólido (m3/día) 14,000 12,000 10,000 8,000 6,000 4,000 BL-84 BD2 BD1 Expon. (BD1) Expon. (BD2) Expon. (BL-84) Gasto sólido (cumulativo, m3/día) 14,000 12,000 10,000 8,000 6,000 4,000 y = e x BD1 y = e 0.002x BL-84 BL-84 + BD2 BL-84 + BD2 + BD1 Expon. (BL-84 + BD2 + BD1) Expon. (BL-84 + BD2) Expon. (BL-84) 2,000 y = e x y = e x y = e x ,000 1,200 1,400 1,600 Gasto líquido (m3/s) BD2 2, y = e x ,000 1,200 1,400 1,600 Gasto líquido (m3/s)!!! At low discharges, bottom transport is significant but increases slowly with discharge! Transport close to the bottom increases more rapidly, because of the increase in turbulence! Transport in suspension, very low at mild discharges, augments more rapidly with discharges than transport close to the bottom! HYDREUROPE

46 A weir to control the flow, a weird idea! The studies of the weir (numerical and scale models) did not properly contemplate sediment issue!! The weir induced formation of an ample sand bar in the centre of the river, upstream of this weir!! The result has been outflanking with strong erosion of the left river border, what produced more downstream an orientation of the flows to the banks, with again strong erosion etc., etc.! HYDREUROPE

47 Carrizal Samaria! The Carrizal riverbed will continue widening, with aggradation of the bed!! However, the Samaria riverbed rises probably more rapidly! HYDREUROPE Strong erosion

48 WEIR STRUCTURE TO CONTROL FLOW IN CARRIZAL HYDREUROPE

49 HYDREUROPE

50 HYDREUROPE

51 Impact of the weir structure! Besides bank erosions, the sediment deficit may cause ever more degradation of the riverbed, with a risk for destruction of bridges and other fluvial structures (Comment: there was a very important exploitation of riverbed material in Carrizal)!! or the destruction of the weir during a flood event, by deepening of the riverbed! HYDREUROPE

52 Impact of the Samaria bridges! The Samaria bridges have a long-lasting effect on sediment retention of sediments, riverbed aggradation and formation of bars and canals (remember the case discussed by Jean Cunge, although only about flow)!! These bars deflect the flow towards the banks, creating an ever more complex riverbed morphology!! This riverbed morphology causes always more bank erosion, resulting as usual with ever more protection (at least, contractors are happy to build the bank protections )! HYDREUROPE

53 Impact of the Samaria bridges! A groyne field has been constructed to protect the right bank of the Samaria upstream of the bridges!! However, these protection works are not very effective, as the river flow attacks the bank with an oblique orientation! HYDREUROPE

54 Impact of the Samaria bridges Samaria bridges HYDREUROPE

55 HYDREUROPE

56 2000 Samaria meandering (canaliform) Samaria braided Carrizal canaliform HYDREUROPE

57 What are possible solutions? 1.! Avoid rapid fluctuations of the flow discharge en Peñitas (new compensation dam?)! 3.! Training the Samaria river between the bifurcation and Samaria bridges (proposal with three types of structures):!!!! A guiding structure with piles, mesh and stones! A series of permeable groynes, with piles and mesh, and longitudinal one connecting them (retard structures)! Bottom vanes to incise the channel (Possibly, through helical flow effect)! HYDREUROPE

58 A river training project (now planned ) HYDREUROPE

59 What does this case study learn us?! The impact of dam construction and operation on the hydrological and sedimentological regime and on the morphological behaviour of rivers has to be recognized properly!! Management of rivers in deltaïc systems must take into account sediment transport and morphology, but numerical models can not presently cope with sediment and morphology, so field investigations (more than field surveys) and mobile-bed scale modelling is required in addition (as well as expertise)! HYDREUROPE

60 What does this case study learn us?! For some rivers, design of bridges and culverts may not be based on hydraulic solely, sediment transport and morphological analysis must also be accounted for (I refer to Jean Cunge s presentation)!! There is a problem with river engineering, as most of it is made by applying (blindly) kitchen recipes, without understanding the functioning of the river (especially morphology and sediment transport)!! River engineering should take into account the past, present and future changes in the river system! HYDREUROPE

61 Thank you for your attention! QUESTIONS AND/OR REMARKS?! HYDREUROPE