ABSTRACT
Drainage is an essential component of road construction.

In most designs of the road, the first thing to be put in place is drainage system.

The presence of blockage in drainage system tends to reduce the carriage capacity of drainage and thereby affect life span of the road.

The research employed a research survey in order to obtain the information that would describe the causes of blocked drainage, canal and culvert in Ilorin-west local government road and its effect on the surrounding environment and the road users.

Data collection techniques used includes questionnaires, photographs and observation.
The results show that Ilorin-west local government road drainage system was not adequate to satisfactorily drain the runoffs due to the blockage caused by debris, illegal dumping of refuse, Non-channelization e.t.c.

As a result, the surrounding environment was greatly affected by washing away some sections of the road and bridges, creation of gullies on land, washing away of the fertility of the land.
The drainage facilities could be improved by frequent inspections, maintenance of gabions built for remedying of gullies and construction of water conservation structures e.g. water pans to hold and reduce the speed of water.

Some drainage, canal and culvert system on Ilorin-west local government road should be redesign.

CHAPTER ONE
1.0 INTRODUCTION
Nigeria is the most populous country in Africa. At the census of November 1991, Nigeria had 88, 514,501 with an inhabitants and a population density of 95.8 per 59 km.
The average annual growth rate between 1963 and 1991 is 1.7% (Baiye E; 1991).

According to 2006 census figure, Nigeria had a population of 140 million people.

The major hazard experienced in Nigeria includes flooding, erosion, deforestation, land degradation and climatic drought.
Flooding in Kwara state has been due to natural or artificial occurrences of blocked drainage, canal and culvert due to solid waste, wash away of the top soil, debris like trees, and leaves present in the water channel.

Flooding has been experienced in different part of the state especially in Ilorin west local government area of the state, which has claimed life, damaged properties of the people that reside in the geographical area and as well as damaged the road pavement to greater extent.
Drainage is the process of removal of surface or subsurface face by water from a given area by natural or artificial means. (Adeyemi, 2005).

The term is commonly applied to the removal of excess water by canals, drains, ditches, culverts and other structure designed to collect and transport water earlier by gravity or by pumping.

A drainage project may involve large scale reclamation and protection of marshes, underwater lands or lands subject to frequent flooding (Microsoft- Encarta 2009).
Canal is an artificial waterway for navigation and irrigation, etc. it is a long narrow arm of the water penetrating an inland.

Canals are man-made channel for water conveyance (Supply), or to services water transport vehicles. A true canal is a channel that cuts across drainage, making a navigable channel connecting two different drainage basins. Most commercially important canal of the first half of the 19th century were a little of each using rivers in long stretches and divide crossing canal in others.

This is true for many canals still in use (Donald Lang mead, 2013).
A culvert is a conduit used as an artificial channel under a road way or embankment to maintain flow from natural channel or drainage ditch (Oshunkey, F.E (1992).

A properly design culvert will carry the flow without causing damaging, backwater, excessive construction or excessive outlet velocities.

Culverts usually have span less than 6m per cell (\www. Acclimated.com), (Albert transportation (2004)).
Blocked drainage, canal and culvert are caused as a result of high population of people living in a geographical area without the proper management of waste disposal, falling trees.

Virtually every Nigerian is vulnerable to flooding either by natural or artificial.
2.0 STATEMENT OF THE PROBLEM
Ilorin-west local government area has been experiencing severe blocked drainage, canals and culvert over the years, which has makes life very hard for the residential in the area and result to loss of life and property.
It has rendered some people homeless and jobless; it is dangerous for the possibilities of infliction by diseases such as cholera, typhoid, fever, malaria etc. as a result of enhancing stagnant water.

It also forces many occupants to relocate due to air pollution and others factor causes by blocked drainages, canal and culverts
3.0 AIM AND OBJECTIVES OF THE PROJECT
The aim of this project work is to investigate into the causes of blocked drainage, canal and culvert in Ilorin-west local government area of Kwara state in Nigeria.
THE OBJECTIVES:-
1. To look into the factor that causes blocked drainage canal and culvert.
2. To find out the hazards which blocked drainage canal and culvert causes to human environment.
3. To find out the various control measures needed to bring blocked drainage under control.
4. To suggest a proper drainage, canal and culvert management.
4.0 JUSTIFICATION
The construction of drainage, canal and culvert in the country is given much of structural or engineering consideration with little or no environmental impact assessment of the operations after the design and construction.

The environmental problem results from operation which are usually devastating.
Hence, this study significantly addresses the following issues.
• Identify the environmental hazards associated with the drainage, canal and culvert.
• Evaluate the magnitude or significance of the hazard and effect.
• Identify changes in downstream hydrology.
• Identify changes in downstream morphology caused by altering the flow pattern.
• Examine control techniques to eliminates or lesson the severity of the effect and to manage the hazards.
• Develops plan and procedures to manage the environmental changes due to the operation of the drainage, canal and culvert.