LAND USE PLANNING IN NIGERIAN

LAND USE PLANNING IN NIGERIAN

          Introduction

Land use planning is historically about management of problemsemanating from growth and change. At the inception of physical; planning, its activities were directed towards improving the health, safety and visual quality of the physical environment. The British government introduced land use planning practice in Nigeria during their rule in 1860-1960, but the Lagos township improvement ordinance of 1863 actually marked the beginning of physical or land use planning in Nigeria, and was aimed art controlling developments and urban sanitation in Lagos.

The Lagos Township ordinance was extended to cover the entire countryafter being amended and renamed as the township ordinance No. 29 of 19 17, and was concerned with the classification control, and regulation ofconstruction of buildings, streets, and bridge within them. The wide scopegiven to it gave rise to it’s being seen as the first systematic attempt at land use planning in Nigeria. It’s main aim was the board principles of municipal responsibility, segregation between European rules and the African, Environmental Hygiene and Sanitation.

In 1928, the Lagos Township ordinance was enacted following the outbreakof bubonic plague in Lagos. As a result, the Lagos Executive Development Board was setup in 1929 as the authority responsible for planning and development Lagos. 1928 town and country planning ordinance (No. 4) based on the 1932 town and country planning act of the United Kingdom.

Shortly after independence in 1960, there was increase in population which resulted in the growth of towns and cities, and this necessitates some control mechanism to ensure orderly development of settlements inNigeria.

In 1978, land use act was enacted to curb land speculates, ease process of land acquisition by government. The 1946 town and country planning law remained in force until 1992 when the first indigenous urban and regional planning law was enacted (Decree 88 of 1922). The law provides a binding legal basis that is most current and matching the tempo of changes for physical and development activities throughout the country.

          ROLE AND FUNCTION OF LAND USE PLANNING

i.        The main task of town planning is to reconcile competing claims for the use of limited land so as to provide a consistent, balanced and orderly development of land use (Foley, 1960’s).

ii.      The central function of land use planning is to provide a good physical environment, a physical environment of such a good quality meaning and development essential for the promotion of a healthy and civilized life.

iii.   Town planning as part of a broader social program (Foley, 1960) Also function to provide low density residential areas, faster local community life and control sprawl or conurbation growth.

          NATURE OF LAND USE IN NIGERIA

In most urban areas, land use has not effectively put under control. Most developers adopt various means to get structures in place in any part of the city.

Most Nigeria towns are undergoing rapid urbanization process; master plans are by nature too rigid to change easily in period of urbanization. Thus no sooner are the prepared that they become out of context with reality because of rapid development associated with cities of the 20” century.

          ZONING SYSTEM

Zoning system is a process through which a community divides itself into two or more district or zones allowing only designated land uses in each district and imposing certain development activity. Adopting a zoning ordinance is an exercise of regulating powers and ordinance provision must be reasonable, based on a comprehensive plan and related to health, safety, morals and general welfare of the community. Zoning is one of themany measures of government to guise the use and development of privately owned real estate.

Rural zoning is not nearly as wide spread as urban zoning, it early use was to reduce public service costs and prevent personal hardship in land cleared areas.

In Nigeria, especially the Federal Capital City (FCC) zoning is considered a useful tool for combating problems such as:

i.                   Protecting public health and safety by preventing development that could lead to ground and surface water pollution, keeping flammable structures at distance apart.

ii.                 Preservation and developing the economic base. This is of particular significance in areas where economic existence is based on natural resources, such as agriculture, recreation or running.

iii.              Improving the quality of the physical environment by screening or eliminating unsightly uses of land use as junk poles and damps, prevent lake pollution etc

iv.              Protecting properly values from being undermined by the development of incompatible uses on adjacent or nearly properties.

          ZONING REGULATION

There are three ways to categorized regulation contained in zoning ordinance.

i.                   The first distinguished between regulating provisions that seek to control the location of different kinds of land uses and those intended to influence characteristics controlling provisions concerning physical aspects within the boundaries of the plot, or tract of land involved as such as the relative position of improvement and the amount of open space.

ii.                 Zoning regulations can also be categorized according to the geographic area of application.

iii.              The third classification separates zoning restriction according to the physical characterized that are affected such as:

a. Those intended to determine population density such as lot size and coverage and type of dwelling.

b. Those concerning land structure relationships minimum set back distance, frontage, and side yard and backyard requirements for residence are almost universal.

c. Those directly controlling land use list of permitted, conditionally permitted, and prohibited uses are set-aside in certain land areas.

Understanding Engineering Surveying, (Alignment and Route Location). Steps/Procedure

Understanding Engineering Surveying, (Alignment and Route Location). Steps/Procedure

In the course of road construction, before finalizing the Alignment of our highways, there are generally four (4) guidelines for the Alignment and the Route Location also known as the Engineering Surveying of the highway that must be carried out. These include

1.     Desk Study Or Map Study  
2.    Reconnaissance (Recce) Survey 
3.    Preliminary Survey
4.   Final Survey (Location Survey)

1.  Desk Study or Map Study:-

           STEPS:

                                 i.      Get the topographic map of area (if available), the likely intended route of the road   may be marked on it.

                               ii.      Study all available information in the office for contours, ponds, valleys, lakes, mountain pass, bridge etc.

                              iii.    Study town planning master plan drawing if available

                             iv.      Also you can Study the Aerial photographs and remote sensing imagery of the area (if available) they are great source of information on topography, terrain, drainage etc.

      2     Reconnaissance Survey:-

             

     After desk study, Reconnaissance Survey is next, it start with a field inspection by walk or driving  or both and necessary information should be collected.it can be conducted in the following  

procedures:

                                 i.            Detail of route vis-à-vis topography of the area, whether its hilly or rolling or plain

                               ii.            Length of the road along various alternatives

                              iii.            Bridging requirements (number, length etc.)

                             iv.            Geometrics: 

·         Gradients that are feasible, specify the extent of deviation if any,

·         Curves and hair pin bends, etc.

                               v.            Right of way available

                             vi.            Existing means of communication i.e. car track, path, mule path etc.

                            vii.            Terrains and soil conditions i.e.

·         Geology of the area

·         Drainage characteristics of the area including area susceptible to flooding

·         General elevation of the road

·         Location of sand dunes.

·         Type and extent of vegetation, etc.

                          viii.            Climatic condition

                             ix.            Facilities/Resources

         3.      Preliminary Survey:

This is a relatively large scale investigation conducted to collect all physical information       which affects the proposed location of the new highway. During this phase of survey, the topographic   features and other features like houses, places of worships, etc. are tied to the transverse line. Longitudinal sections and cross-sections are taken and bench marks established. This data form the basis for determination of final center line of the road.

Procedures:

                                 i.            It starts with the running of a traverse along the selected route, adhering as far as possible to the probable final center line of the road, in difficult situations, a secondary transverse may be introduced.

N.B: Transverse consists of a series of straight lines with their distances and intermediate angles measured very carefully.

                               ii.            Transverse should be done with theodolite and all angles measured with double reversal method. The distance along the transverse line should be measured with metallic tape or chain.

                              iii.            Physical features like buildings, monuments, place of worships, schools rail line etc. that are likely to be affected by the project should be located by means of offsets measured from the transverse line.

                             iv.            Leveling work should be kept to the minimum. Generally, fly levels at 50m intervals, and at all intermediate breaks in ground should be taken along the transverse line.

      4.     Final Survey (Location Survey)
 

The purpose is to fix the center line of the road or selected alignment in the field and to collect additional data for the preparation of the drawings. if preliminary survey is properly done,final survey data collection will be limited

Procedure:

 

         i.            Staking (pegging) out the final center line of the road by means of a continuous transit survey

·         Process whereby the center line of the road as determined in the design office, is translated on the ground by means of a continuous transit survey and staking or pegging of the center line as survey proceed, fixed at 50m intervals in plain and rolling terrain, hilly, 20m intervals. All angles measured with theodolite

       ii.            Detailing leveling

Lesson Note On Establishing a site master benchmark

Establishing a site master benchmark 

One of your fist tasks as a site engineer on a new site is to establish height control. 

It is usual to establish a site Master Bench Mark (MBM) from nearby Ordnance Bench marks and the following lists the usual procedure 

a) The Master Bench Mark must be constructed in apart of the site clear of any construction activity and must be of very stable construction. 

A typical MBM comprises a steel pin firmly driven into the ground and surrounded by concrete. Provide protection by surrounding it with a fence and the reduced level of the bench mark should be written on that fence as well being recorded in the field book. 

b) The reduced level of the MBM is found by flying leveling from a nearby Ordnance Bench Mark (OBM) using the MBM as a change point (intermediate sights are not permitted) and then closing the circuit onto a second bench mark, if such exists. This not only provides the closing error but also checks the OBM for any possible movement.

 c) The leveling operation must be carried out a minimum of three times, ensuring that a good closing error is obtained each time. The range of results must not exceed 5 mm, if it does then further leveling must be carried out until such a range is achieved. The mean value can then be adopted as the MBM level. 

d) Having established the MBM, any number of temporary bench marks (TBM) can be located and leveled where and as required, working to the same order of accuracy as above. 

The ideal situation regarding TBMs is to locate them in such positions that a level can be set up anywhere on the site and be within sighting distance from it, thus avoiding the need to fly level to the area of operation.

Maintenance of Levelling Equipment

Maintenance of  Levelling Equipment A) Levels (i) Store in a dry, secure place (ii) If the instrument gets wet, all surplus water should be removed with a dry cloth, using a clean tissue for the lens. Store the instrument in a warm secure place with the lid removed, to dry. (iii) Do not oil moving parts, clean them with a dry cloth. B) Tripods(i) Clean them at the end of each working day. (ii) Store them in a closed position carefully, and not thrown in the corner of a site hut. Remember that the purpose of a tripod is to provide a stable working base for the level. It will not do this if mishandled. (iii) Ensure that tripods feet do not become loose. (iv) The clamps on tripods legs tend to become less effective after long usage. Do not use nails, paper, etc., in order to tighten the legs, move the clamps further along the leg. (v) Bolts securing the tripod top to the legs work loose regularly – keep them tight. C) Levelling staves i) Clean each day after use and store correctly. ii) Wooden staves swell if wet. Take it apart and wipe off surplus water. Allow to dry naturally before reassembly.

Lesson Npte On Introduction to Drainage and Dewatering

Introduction to Drainage and Dewatering

What is drainage?

As the name itself suggests, drainage is the process in which the free water is removed with the help of gravity in order to maintain stable soil conditions.

Drainage can be classified into two categories:

1. Surface drainage
2. Sub-surface drainage

What is Surface drainage?

The water that runs on the surface of the ground is collected and or diverted into a water body.

Sub-surface drainage

It is the collection and disposal of ground water. It is also called as dewatering.

What is dewatering?

The process in which the water is removed from a foundation pit;

• when it is situated below the ground water table or
• when it is surrounded by a coffer dam.
• 

Why is dewatering done?

Only understanding the definition of dewatering is not enough. It is essential to know the reason as to why it is done.

Some times in some areas, the water table is high. This causes trouble and discomfort during construction. The water is pumped out so as to keep the excavation dry. Excavation has to be kept dry so that concreting can be done.

Sometimes temporary dewatering may suffice. Temporary dewatering is draining out the water at the time of construction and it is then followed by restoration to its original water level as soon as the construction is complete.

What is permanent dewatering and why it is done?

Permanent dewatering is removing the subsurface gravitational water throughout the life of the structure. This is done to protect the structure from moisture and dampness.

Advantages of Subsurface drainage

It helps in improving the properties of the soil

Helps in the stabilization of soils

Let us consider the case of “Fine grained soil”

The water removed from fine grained soil is not much but the improvement in the properties of the soil is significant.

Helps in reducing hydrostatic pressure acting at the base of the structure

Methodology to be adopted for Sub-surface drainage:

The methodology adopted at a site would depend on various factors. They are as follows:

• Characteristics of the soil
• Position of the water table
• Time period.