Environmental Issues in Sustainable Project Development

Contents• Introduction – Water Cycle and

Contamination, Nutrients Cycle and Its Disruption

• Introducing Major Environmental Issues/Problems

2

Introduction

• Many countries have implemented numerous environmental laws and regulations containing provisions for air and water quality management, waste disposal and the protection of natural resources.

• Project development activities include as siting, dredging, land clearance, filling and construction.

• There are planning permits for some of these activities, with its own requirements - to maintain environmental quality and protecting valuable natural resources.

3

Introduction

• Understandable, - especially developers - confused or frustrated by the maze of legal demands of permit processing.

• It is also the case that environmental considerations are not always fully integrated into development planning or implementation.

• A better understanding is needed to take environmental considerations into account in proper planning, design and implementation will assist in reducing the risks of development problems and associated costs.

4

Water Cycle

5

Water Cycle

• The water cycle is the constant movement of water through natural systems. Water falls to earth as precipitation, where it either seeps into the ground, flows along the surface to rivers and streams, evaporates, or is taken up by plants and released to the atmosphere.

• Groundwater flows very slowly through subsoil and bedrock until it enters nearby streams, lakes or other wetlands. Water evaporating from lakes, rivers and the ocean forms clouds; precipitation from the clouds completes the cycle

• The water cycle provides a basic link between natural systems such as forests, wetlands and other aquatic habitats, and is important to man in maintaining water supplies and removing degrading pollutants.

6

Disrupting the Water Recycling

Surface Water

• All surface waters should be capable of supporting aquatic life and aesthetically pleasing

• If need as a public supply, the water must be treatable by conventional processes to yield a potable water meeting the drinking water standards.

• Rivers are also maintained at a quality suitable for swimming, water skiing and boating.

• Surface waters are classified accordingly into three categorize which are physical, chemical and biological quality.

• Criteria defining quality are dissolved oxygen, solids, coliform bacteria, toxins, pH, temperature and other parameters.

Water Pollution

• Dissolved oxygen is important for aquatic life.

• Dissolved solids are important because high concentrations interfere with agricultural, domestic and industrial water uses.

• Toxic pollution, such as heavy metals and pesticides will cause diseases for human and aquatic life.

• The allowable pH range is 6.5 to 8.5 for protection of fishes and to control undesirable chemical reactions.

Classifications of Contamination

1. Point sources: wastewater discharge from outfall sewers or drainage channels.

2. Diffuse sources: pollutions dispersed on the land by human activities in runoff from rainfall and snowmelt. The important sources are agricultural land drainage, surface mining and urban storm drainage.

3. Principal point sources: municipal and industrial wastewater discharges, cooling water from power plants and intermittent discharges such as overflows from stabilization ponds and by-passing treatment facilities

Oxygen Content

• The principle sources of dissolved oxygen are from the atmosphere and alga photosynthesis.

• Solubility of dissolved oxygen is affected by temperature, barometric pressure and salinity of the water

• The diffusion of oxygen into impounded water is a slow process because of the small surface area relative to the volume of water.

• During circulation by wind mixing, oxygen equilibrium at the prevailing water temperature is established quickly in moderately deep lakes.

Eutrophication

• The phenomenon of eutrophication is used to describe the normal processes that occur in lakes and lead to their eventual extinction.

• Cultural eutrophication is the accelerated fertilization of lakes, reservoirs, streams and estuaries arising from pollution associated with population growth, industrial development and intensified agriculture.

• The response of aquatic ecosystems to increased input of nutrients is greater productivity to the detriment of water quality.

• The process of eutrophication is directly related to the aquatic food chain.

:

• Algae use carbon dioxide, inorganic nitrogen, and orthophosphate and trace nutrients for growth and reproduction.

• These plants serve as food for microscopic animals (zooplankton).

• Small fishes feed on zooplankton and large fishes consume small ones.

• Productivity of the aquatic food chain is keyed to the availability of nitrogen and phosphorus, often in short supply in natural waters.

• The amount of plant growth and normal balance of the food chain are controlled by the limitation of plant nutrients.

• Abundant nutrients unbalance the normal succession and promote blooms of blue algae that are not easily utilized as food by zooplankton. Thus, the water becomes turbid.

• Algae also settle to the bottom, reducing dissolved oxygen.

• Shorelines and shallow bays become weed-choked with the prolific growth of rooted aquatics.

Reservoir

Groundwater Pollution

• Groundwater contamination commonly results from human activities where pollutions, susceptible percolation, are stored and spread on or beneath the land surface.

• Pollution sources are industrial wastewater, sanitary landfills, storage piles, absorption fields following household septic tanks, improperly constructed wastewater disposal wells, application of chemicals on agricultural lands

• The amount of water available for infiltration, either from precipitation or the wastewater itself, is a primary factor in carrying pollutions down through a soil profile.

• Contaminations are influenced both physically by soil porosity and hydraulically by the rate of water movement.

Source of pollution

Natural Contamination

• Principal natural chemicals found in groundwater are dissolved salts, iron and manganese, fluoride, arsenic, radionuclides and trace metals

• Both geologic and climatic conditions influence mineral composition.

• In arid regions with limited water recharge, slow percolation results in mineralized, poor quality water high in sodium chloride.

• In humid climates, weathering of sedimentary rock releases calcium and magnesium, creating excessive hardness and often dissolved iron and manganese.

• Fluoride is a constituent of mineral fluorite found in sedimentary, igneous and metamorphic rocks.

• In some region, high concentrations of fluoride in groundwater result in fluorosis (mooting of teeth) and bone damage.

• Arsenic can be a significant problem in aquifers of volcanic deposits where concentrations are higher than the maximum contaminates level.

• Geological formations containing radioactive minerals often contain large amounts of organic matter in the form of lignite or phosphates occurring as phosphatized bone or shell materials.

• Small amount of metals such as selenium, cadmium, lead, copper and zinc are found in rocks and unconsolidated deposits.

• Groundwater generally contains only traces of these metallic elements, and their presence is rarely a water quality problem.

Contamination from Domestic Wastewater

• A serious source of contamination can be subsurface disposal of domestic wastewater through septic tank absorption fields.

• The purpose of an absorption field, which consists of perforated pipe laid in gravel-lined trenches, is to allow the water to seep down into the soil profile.

• With a high density of this unit, serious contamination of the groundwater can occur.

• If the soils permeable, shallow water wells are potential sources of mobile pollutions like detergents, chloride and nitrate ions and viruses.

Burial Activity

• Burial of solid wastes can result in degradation of subsurface water through the generation of leachate caused by water percolating through the refuse fill.

• Leachate is highly mineralized water containing such constituents as sodium chloride, nitrate, and trace metals and variety of organic compounds.

• Pollution problems are more likely to occur in humid climates where rainfall exceeds the absorption capacity of the disposal area.

Industrial and Commercial Sources

• The majority of all hazardous wastes from manufacturing are disposed of on the land, mainly because this method is usually the cheapest waste management option

• Industrial wastewaters and sludge are discharged to impoundments, buried in landfills, or injected in deep saline aquifers.

• Source of pollution - Impoundments including lagoons, basins, pits and ponds are a potential source of contamination because of the possibility for leakage of hazardous substances.

25

Water Cycle

• Water evaporating from lakes, rivers and the ocean forms clouds; precipitation from the clouds completes the cycle.

• The water cycle provides a basic link between natural systems such as forests, wetlands and other aquatic habitats, and is important to man in maintaining water supplies and removing degrading pollutants.

• As water moves through the cycle, it changes state between liquid, solid, and gas phases. Water moves from compartment to compartment, such as from river to ocean, by the physical processes of evaporation, precipitation, infiltration, runoff, and subsurface flow.

26

Water Cycle

• Water cycle strategic plan addresses 2 major questions:

1. What are the effects of large-scale changes in land use and climate on the capacity of societies to provide adequate supplies of clean water.

2. How do natural processes and human activities influence the distribution and quality of water within the earth system and to what extent are resultant changes predictable?

27

Nutrients Cycle

Basic Plant Nutrient Cycle

30

Nutrients Cycle

• The nutrients cycle including organic compounds and minerals is essential in maintaining natural systems. Mineral elements from rocks are made available to plants and animals by weathering, and by dissolving and entering the water cycle.

• Nutrients in the soil are taken up by plants and passed on to grazing animals and finally predators. They are returned to the soil through decomposition. Additions to the nutrient cycle occur through precipitation and wind-blown dust, and nutrients are lost through erosion and runoff, hunting, and harvesting of trees and crops.

31

Nutrients Cycle

• Environmental disturbance may cause more nutrients to be lost than are added, upsetting the nutrient cycle of an area and decreasing its productivity.

• Soil organisms store the fertility of the soil in their bodies. Their varied make-up (bacteria, fungi, worms) matches the aboveground vegetation closely.

• When forests are converted to crop fields, runoff and seepage increase, whereas evaporation decreases. At the same time, fertility is disappearing by a substantially increased dissolved matter (nutrients) flow. The temperature increases and evaporated moisture rises much higher.

32

Soil

33

Soil

• Soil develops over time by weathering of bedrock and the combined action of local climate and living organisms on bedrock and accumulated material.

• The most common of soil is alluvium, which consists of the clay-loams, clay and silt, or coarse gravel and sands. The ability of groundwater to travel through alluvium is directly related to the amounts of silt and clay; the more silt and clay the slower the water will travel.

• Sand and gravel deposits contain very little silt and clay, and groundwater can travel through them very easily. Such deposits are usually found in river valleys.

• Large sand and gravel deposits that are saturated with groundwater can often be used as sources for water supply.

34

• Soil consists of mineral and organic matter, including living organisms. Soil is among our most important natural resources because of its position in the landscape and its dynamic, physical, chemical, and biologic functions.

• Soil erosion loss is caused by wind, water movement in response to gravity. Erosion is an intrinsic natural process, but in many places it is increased by human land use. Poor land use practices include deforestation, overgrazing, and improper construction activity.

• The influence of agricultural practices such as irrigation, groundwater pumping, fertilising, spraying should be considered all the way down-slope.

O) Organic matter: Litter layer of plant residues in relatively undecomposed form.

A) Surface soil: Layer of mineral soil with most organic matter accumulation and soil life. This layer eluviates (is depleted of) iron, clay, aluminum, organic compounds and other soluble constituents. When eluviation is pronounced, a lighter colored "E" subsurface soil horizon is apparent at the base of the "A" horizon.

B) Subsoil: Layer of alteration below an "E" or "A" horizon. This layer accumulates iron, clay, aluminum and organic compounds, a process referred to as illuviation.

C) Substratum: Layer of unconsolidated soil parent material. This layer may accumulate the more soluble compounds that bypass the "B" horizon.

35

Soil

36

Soil

37

Soil

38

Aquatic Food Web

39

Aquatic Food Web

Invertebrates

Plants

41

Aquatic food web

Aquatic food web

Aquatic food web

45

Aquatic Food Web

• The food web of coastlines and rivers begins with dead plant and animal matter flowing into rivers and estuaries from upland areas. Converted into food by shoreline vegetation (including algae), bacteria and minute floating plants (plankton).

• The plants are eaten either by small fish, shellfish and other invertebrates, or by microscopic floating animals, (zooplankton) which, in turn, are preyed upon by larger animals. Large fish, birds and man are at the top of the food web, the latter having no natural predators.

• Other animals feed on dead plants and animals, reducing them to basic chemical constituents. These materials are used by plants, thus completing the cycle.

• Because all aspects of the system are interrelated, disruption of one part of the food web can affect many other parts.

Common Issues in Construction Projects

1. Land disturbance – erosion, contaminated stormwater, sediment, dust, flood

2. Noise and vibration

3. Waste