Rio Rimac 395 years of evolution and other imbalances The differences that arise in the daily evolution of a river, generally go unnoticed by anyone, but is the main source of natural water in the city of Lima (capital of Peru) and talking about the second desert city's largest world after Cairo (capital of Egypt), the Rimac river practically made possible urban empowerment of the valley with slopes as the basin water limitations. In a matter of infrastructure is true that Lima need and need room to grow and unfortunately over the last centuries most of the banks and natural flood plains of the river Rimac, were invaded, causing a rash of city living - the river and punishment respective non-conservation and deprotection, used for many centuries almost the only collector of debris from the big city (there are many places that receive input from waste, as well some parts restored). This team: city - rio ( Rocha, "Introduction to fluvial hydraulics", 1998 ) should now be interpreted in the best shape possible for managers to assume governmental responsibilities and support us unconditionally.
395 years of difference reflected the larger photographs of the year 1613 when Lima was a dozen blocks to the stone bridge a connection with Rimac area.
Fig 1. Plano de Lima 1613.
Fig 2. Satellite view of Lima, December 2006 Google Earth.
With a rapid appreciation, the avenues Zarumilla Beltway around and around housing estates would floodplain of the river Rimac and a balance fluviomorphological slope and width (according to the theory of Lane and balance in rivers, 1955), considering that in 1613 it had a width of 320 m river today is 40 m on average. the river has increased its depth (eroded), due to narrowing along its path (at gunpoint), which is currently seen in the erosion near the bridge down from Dueñas and as far as the bridge of the Army, the latter with an infrastructure of protection for the bridge is not literally hanging by regressive erosion.
Fig 3. Rio Rimac, at gunpoint and plan view of the bridge gap with the Army and waterfall.
This is the result of 395 years of urban desplanificacion and attempts to stop the erosion down:
Fig 4. Waterfall, climb of approximately 15 meters, Rimac River - Bridge of the Army.
To this let us add the problem of sedimentation that is generated downstream from the bridge Faucett, due to severe narrowing occurred upstream, reflecting a very interesting case of evolution fluviomorphological to quantify with scientific research
other hand
In these last years have restored two major sections of the river on the basis of slope compensation works, these are works cross in a section of river (ties), generating small sections with sufficient features for the conservation of species and the accurate assessment of the erosion and sedimentation. Another section restored for landscaping was found between the bridges of Abancay Avenue and Santa Rosa Avenue.
After this brief account, it is logical to think that will continue to make important and much needed work for us, the beneficiary population, bridges, desilting of channels,, river defenses or playgrounds, but left in doubt whether such strictures conceived in the design are enough to contain a historic avenue Rimac River, this is a separate issue, see you soon!
Fig 5. Traviesa - Rio Rimac, section parallel to the highway restored Priale Ramiro.
NOTES:
"Many of the works and / or projects mentioned in this post, develop as work items in the National Engineering University in the class of" Introduction to Hydraulic river "of the Faculty of Civil Engineering.
"The theory of the phenomenon of degradation and aggradation of the river Rimac river in the section presented, was raised by Dr. Rocha Felices past decades.
Fig 1. FLO 2D model application and determination of hazard maps. 
