Water Resources Conservation Effort to Preserve the Forest Function

Existence the forests as part of a large ecosystem has a meaning and important functions in life support systems. Various large benefits can be obtain from existence the forests through its function as a provider of water resources for humans and the environment, carbon absorption capacity, suppliers of oxygen in the air, tourism service providers and regulating the global climate.

In forest management, it is time to be encouraged to consider the benefits, functions and benefit or loss would be done if the forest exploitation activities. How many values of the function lost due to logging activities in areas that have strategic value as in the forest area in the upper watershed, so that these considerations can be using as input and material considerations in planning and forest management to Indonesia.

For Indonesian version can be downloading here (just clicking) free in PDF form.

Due to more of land that had been convert into a catchment area to be agricultural andresidential areas would cause the disruption of regional water cycle. In the coming 21st centurywill increasingly be felt natural limitations in providing water for life. Total water supply comesfrom the rain area is relatively fixed, being felt not offset the level of need.

Abundance of water resources owned by Indonesia does not guarantee the abundant availabilityof water area in the dimension where time and dimension. Climate variation and vulnerability of water resource systems to climate change will worsen the status of the water crisis is the increasing frequency of floods and long droughts, so that water availability increasingly unable to offset the increased need for water for various uses.

Beside, with the accelerated economic growth, demand for water resources both quantity and quality has increased too, and in certain places exceed availability. These causes the water resources can become scarce goods.

Forest Function

Forests with broad distribution, with a diverse structure and composition are expecting to provide huge environmental benefits to human life, among others, reduction of flooding, erosion and sedimentation and hydrological cycle control.

Hydrological Circle

The function of forests in the hydrological cycle control can be grouping as follows:

a.    As a deduction or waste water reserves on earth through the process :

·   Evapotranspiration

·   Plant water consumptive use to the formation of body tissues

b.    Adding water vapor in the atmosphere

c.    As barriers of water fall to the earth by interception process.

d.    As reduction of the kinetic energy of water flow through

·   Direct retarder to soil surface by the trunk and branches of trees

·   Retarder against surface runoff by trashed foliage.

e.    As pusher to improving the ability of the physical soil characteristic to water infiltration through roots system, the addition of organic matter dynamics or the increase in soil biological activity.

The function of forests as the controlling hydrological cycle can be saw from two points of view, which provides water to the concept of water harvesting and with the concept of water yield.

The amount of water that could be harvested depending on the amount of surface flow (run off) that can be used, while the amount of water that can be produced depend on ground water discharge. Both these objectives require different treatments.

To increase water harvesting, infiltration and percolation to be controlled, is to increase the income of water, infiltration and percolation precisely who should be increased. The concept of producing water to the principle of water resources development in the area of wet climates, because the concept of water harvesting would bring great risk, by increasing erosion and will also waste a lot of land to contain it.

All functions of the forest are a dynamic environment that will change from season to season and from year to year. In the state of forests that have been establish, changes in forest function may only appear seasonally, according to the pattern of rain distribution.

The function of forests to control the water cycle starts storing water as a function of canopy water interception. Until now, interception is not considering as an important factor in the hydrological cycle. For low rain areas and water needs met by the concept of water harvest then the managers of the Watershed must still take into account the amount of interception because the amount of water lost as interception of water can reduce the amount of water that goes into an area and ultimately affect the regional water balance. Thus, maintenance of forest thinning is essential conducted according a predetermined frequency.

The second main function also often a source of public concern is evapotranspiration. Several factors play a role against the amount of evapotranspiration include solar radiation, temperature, air humidity, wind speed and water availability in the soil or often called soil moisture. Soil moisture contributes to the occurrence of evapotranspiration. Evapo-transpiration has an important influence on the amount of groundwater reserves, especially for low rainy region, layer / thick shallow soil and rock properties that cannot store water.

The third function is the ability to control the high forest soil moisture. Soil has the ability to store water (soil moisture), because they have cavities that can be filled with air / liquid or is porous. Sections soil moisture which cannot be remove from the soil by natural means is by osmosis, gravity or permanent storage capacity of the soil can be measured with the soil water content at permanent wilting point that is at the lowest soil water content where the plant can extract water from the soil pore space to the force of gravity. Wilting point is the same for all crops on certain lands (Seyhan, 1977). In this wilting point moisture, level of plants could no longer absorb water from the soil. The amount of water collected in the root zone is an important factor for determining the critical value of agricultural land and forestry.

The fourth function is the flow control. Most of the problems of distribution of water resources are always associated with the dimensions of space and time. Lately we are more often finding with a condition of excessive water in the rainy season and water shortages in the dry season. Until now, still believe that good forest capable of controlling the water cycle of forests is a good means to store water during rainy season and releasing it in the dry season. This belief is based on the hearts of society still attach evidence that many water sources in the area of good forest remains flowing in the dry season.

From the above description, it seems clear that the function of forests as providers of environmental services through its ability as a regulator of water has a value of critical importance in supporting the livelihoods of communities around the forest.

However, the function has severely limited by several factors, among others:

a.    The nature of the dynamic growth that depends on the time and season.

b.    The value function is also determined by forest structure, area, species composition,

c.    Growth conditions and location.

d.    The value function for a particular state of forest ecosystems is also limited by the climate, the state geology, geo-morphology and soil characteristics.

Degradation of Forest Functions

Indonesia has millions of hectares of critical land and watersheds is degraded, so that necessary improvements. One way to improve watershed degradation is through tree planting campaign. In addition, efforts will be required to improve policies related to land use and management of critical lands and watersheds.

Various newspapers and non-governmental organizations (NGOs), environmentalists are always highlighted the problem of forest destruction and illegal logging each time the flooding and landslides. The loss of forests was considering as the sole cause of the loss of hydrological functions of watersheds and the people living in the mountains is often considering a cause of damage to the environment.

The cause of degradation of forest function less and much influenced by:

1.     Inappropriate in Land Use and Land Management

Inappropriate in land use and land management at the catchment area became one of the causes to accelerated erosion and directly can be reduce soil productivity, reduce the ability of watershed in the provision of water throughout the year and reduce the quality and quantity of water flowing in river.

2.     Increasing population and  land conversion

Increased population has increased along with the needs of the population will be residential spaces and work space to make some land areas experiencing dramatic changes in function.

The land use change is not accompanied by a spatial arrangement of these good, making watershed hydrological conditions change as well. Primarily this is related to the conservation problems of water catchment areas.

Increasing the number of people accompanying the increasing level of demand for space backers of life and livelihood of residents resulted in pressure on the environment, watershed, and has been widely proven to create new critical area.

3.     Conversion of the border and flood plains function

River’s border arrangement needs at this time become a growing issue in the level of managers and planners of regional development. Seeing this condition of the river border arrangement had been necessary to be done. This involves many things, both in terms of social as well as in terms of the hydrology of the river itself, which to some extent will affect hydro-morphology of the river.

4.     Mineral Exploitation

Exploitation of minerals mining (class C and other classes) in the river resulted in uncontrolled degradation of the river environment.

Degradation of rivers due to mining excavations this C class will continue to arrive at a balance, the magnitude of the average sediment transport in downstream excavation taking C equal to the size of the average sediment transport from the upstream reduced by the class-C excavation conducted. To maintain the condition of river morphology to handling class-C is well dug and equitable among other regulatory improvements, location, licensing and supervision system.

While the exploitation of a higher class of mine has a tendency causes environmental damage and disruption of watershed hydrological cycle within the watershed. This is caused by the exploitation generally done by open pit area is quite large, so clearly the direction of surface flow and subsurface flow within a certain time will move.

Action to Maintaining Forest Functions

The actions to maintain of forest functions conducted by implement conservation of water resources. Conservation of natural resources is the protection and preservation of water resources, water conservation and water pollution control in order to maintain continuity of carrying capacity, the capacity and functions of water resources. Conservation of water resources was doing on rivers, lakes, reservoirs, swamps, groundwater basins, irrigation systems, water catchment areas, nature reserves, nature conservation area, forest area and beach area.

Under the problem of forest function as described above, the conservation of water resources management can be referring to the Indonesian Regulation, i.e. UU No. 7 in year 2004 on Water Resources (UU no. 7 / 2004 can be downloaded for free here), and grouped into three methods, namely (1) in vegetation, (2) by civil construction, and (3) is chemically, with through the social approach , economics and cultures.

However, implementations of conservation actions are generally develop into: (1) non-technical conservation action, (2) technical conservation action civil non-construction, and (3) technical conservation action with civil construction.

1.    Non-technical Conservation

Water Resources Conservation in non-technical civil action grouped again into: (a) Rules and Institutions, (b) the conservation of vegetation.

Conservation Action and Institutional aspects of regulation are the activities that promote and support the implementation of conservation, supervision, monitoring and evaluation and implementation of conservation activities, and providing sanctions against violations that cause change and environmental degradation of natural resources, with the product law, rules and division of tasks and responsibility of activities.

Vegetative conservation is the use of plant or plants and crop residues in such a way to reduce the destructive force / energy that much rainfall into the ground, hold / reduce the rate of soil erosion and improve the charging surface soil moisture and groundwater. Soil and water conservation through vegetative is carrying out its functions through:

a.    Reduce of destructive energy of raindrop that fell from a rain interception by the foliage of plants or plant canopy.

b.     Reduce the volume of surface flow due to increased infiltration by the activity of plant roots and the addition of organic material.

c.    Improve soil water loss due to increased evapotranspiration, so soil water hungry faster.

d.    Slower the surface runoff due increased flow path length by the presence of plant stems.

e.     Reduce the destructive force of surface flow because of the reduction of runoff volume and velocity of surface flow due to increased path length and surface roughness.

Vegetative Conservation can be done by, for example :

a.    Reforestation, increased density of plant stands and closing the open areas.

b.    Closing back / planting new stands on the border river.

c.    Promotion, publication or dissemination to forestry community and GN-RHL.

d.    Increased awareness of the role and the community around the forest area in the maintenance, preservation, and surveillance.

e.   Supervision and monitoring of the implementation of Regulations on forest management, boundaries and illegal logging.

f.      Improved land management in sloping lands, among others:

§    Processing of land according to the contour

      Land preparation and planting according to the contour lines could be reduce the erosion rate to 50% compared with the method according to slope / contour cutting.

§    Contour Bunds

     Contour Bunds function blocks the flow of surface and store water in the upstream guludan and to cut the length of the slope. Contour Bunds effective for slopes less than 6%.

g.     Improved methods of cultivation in the area / slope, among others:

§    In strip cropping

§    Double cropping

§    Use of mulch

2.    Technical Conservation Action

a.    Technical Conservation Action – Non Construction

This conservation action is a supporter of conservation technical civil construction authorities from several agencies.

Activities in these sectors include:

§   The integration and inter-agency coordination and public participation in water resource utilization planning and development in an integrated and comprehensive conservation in watershed Sumbawa / Brang seeds.

§   The result of this activity should be stated in the policy blueprint for regional development and reinforced by laws / rules.

§    Licensing, supervision and monitoring of the utilization of water resources.

§    Rule-making class C mining excavation and river border.

§    Improving the quality of the officer / operator O & M and its supporting facilities.

§    Socialization program biopori residential and office environments.

§    Setting border boundary rivers, lakes, reservoirs and water sources.

§    Installation of boundary demarcation stakes

§    Improving the quality of O & M operator and its supporting facilities

§    Socialization biopori manufacture, infiltration wells, water ponds, etc..

§    Program and tour of the clean river

§    Improved sanitation facilities and infrastructure.

b.    Technical Conservation Action – by Construction

The basic principle in water resources conservation is to reduce the amount of soil lost through erosion and landslides by the energy of water, this mean are one measure of water quality management and physical control of water pollution (dissolved in watercontent of sediments). Whereas the principle of water conservation is the use of rain waterthat falls to the ground as efficiently as possible, controlling excess water rainy season, andprovide adequate water in the dry season (water conservation efforts). In this case, technically civilian conservation has a function:

§    slowing the flow of surface runoff.

§    accommodate and stream flow so as not to damage the surface

§    increase the capacity of water infiltration into the soil and improve soil aeration

§    provide water for plants.

The conservation measures included in civil engineering methods include the following:

1)   Development / Formation of Terraces

Form a slope with a terrace formation is made transverse or cut slope, capture function and directing runoff to stable outlets at non erosive.

The development or formating of land terracing system conducted in the region upstream and middle of watershed at the level of non-protected forest and cultivated land with a slope greater of 6%. This activity is carried out and is on the authority of the Department of Agriculture and Forestry Office.

2)     Development of Reservoir

Development of the reservoir be conducted due to the availability of water in quantity and time are not always consistent with the needs, so that the function of reservoir is the conservation of natural resources from the aspect of Water Resources Protection and Conservation and Preservation of Water, in accordance with one of the goals of conservation of natural resources is to maintain continuity of water throughout the year .

Function follow-up of reservoir development if applied to the body is to reduce peak river flood, so the destructive force of floods can be reduced and minimized, even if it may be abolished.

Another follow-up function is to reducting flood discharge can reduce the energy or the flow velocity so that the force of water against the stability of river banks and river border areas, so that environmental conditions SDA can protected and maintained.
Reservoir as an act of conservation in the watershed should be in form:

§   Water pool

§   Water pond

§   Dam

3)     Construction of Sand Pocket/Ground Sill

Constructing of Sand Pocket / groundsill, to reduce the flow velocity, reduce erosion and capture sediment so it can fix the slope (gradient) river. Construction are  planned in all streams with a gradient greater than 15%, small, medium and large.

4)     Construction of Check Dam

Construction Check Dam, intended to inhibit the flow velocity and capture sediment so it can fix the slope (gradient) river.

This building also can be design and function as a protective structure of existing buildings such as the possibility of lacing material (stone) that carry the flow.

5)   Construction of Retaining Wall, River Bank Protecting and Capturing Water Source

These construction are functioned o avoid damage to watershed recharge areas and springs from damage due to erosion or catastrophic landslide.

6)     Construction of Absorption Wells

Is the disposal of rainfall systems that hold rainwater and soil water filling and reduce runoff. For areas near the coast soil water filling to prevent / reduce the infiltration of seawater into the mainland.

Absorption wells have a working system as follows:

§    Absorption wells should be above the elevation / area dug wells usual.

§    To maintain water pollution of the aquifer, depth of infiltration wells hares above ground water depth is unconfined aquifer that characterized by the presence of spring soil.

§   In the calcareous / limestone karsts hills with deep / shallow solum soil, groundwater depth pads are generally very deep that infiltration wells not recommended. Moreover, either is in tidal lowland where ground water table is very shallow.

§    To obtain a sufficient amount of water, absortion wells should have a rain water catchment in the form of state landscapes either agricultural land or rooftops.

§    Before the rainwater in the form of surface runoff into the well through the water channel, should do the screening of water in the tub control first.

§    Tub control consists of several successive layers is a layer of gravel (gravel),  coarse sand, sand and palm fiber.

§   Filtering intended for the erosion of dust particles from the catchment area does not carry over into the wells so as not to clog the pores of the existing aquifer layer.

§    To curb the kinetic energy of water entering through the inlet, bottom of the well which water-resistant layer can be fill with stones or fibers apart.

§   On the wall right in front of the inlet wells, pipes installed expenditure that is located lower than the inlet connection to anticipate when they occurring overflow / overflow of water in wells. If not equipped with pipes expenditure, water entering the insulation block, etc.

§   The diameter of the well varies depending on the amount of rainfall, catchment area, hydraulic conductivity layer aquifer, aquifer thickness and aquifer layer capacity. In general a diameter ranging antaral-1, 5m

§   Depending on the unstable level / soil conditions and availability of existing funds, the couple painted the walls of wells can brick or concrete buffs. It would be better if the walls of the well made the holes for water to seep also horizontally.

Benefits of absorption wells are as follows:

§    Reducing water runoff, so the drainage network will be minimized

§    Prevent the existence of stagnant water and flooding in downstream areas

§    Maintain high groundwater table that is increasingly reducing, due to the use of water deficit.

§    Reduce / hold water intrusion Links for the area adjacent to the coast.

§   Prevent reduction / land subsidence (land subsidence), due to excessive ground water usage.

§    Reduce groundwater contamination

§    Provide a reserve of water for farming for the surrounding land

§    The cost of construction of infiltration wells are relatively cheap.

§     Impact will further reduce the flood peak discharge, although not very significant (in most cases to low population density area flooding reduction capability is less <10%).

7)     Development of Waste Water Treatment System

The building is required to collect and treat waste-water and industrial households especially in urban areas, before going into the river, so that function to reduce pollutants into the rivers.

Every household or household group must have a waste water processing system. Socialization of the importance of waste treatment installations, and changing habits of society directly dispose river or other water bodies, as well as to provide a household waste treatment system should be made considering the condition of water quality in rivers, especially in the dry season are included in the category of polluted one of them is from a biological element.

8)     Development of Bi-pore System

The purpose of the bi-pore construction is a construction at soil surface that allows rainwater and surface water as much as possible to absorption into the soil, so that this construction serves to reduce runoff, improve infiltration and percolation and increase soil moisture filling with water and increase groundwater. Conservation functions of this construction is the preservation of water and beach area or a particular watershed to reduce downstream intrusion of sea water because the groundwater can be improved.

Some type of construction are:

§   Use grass block or paving blocks as a substitute for concrete block or asphalt penetration layers on the road, carport, yard, shopping center and offices block.

§    Use of the drainage hole at bottom canal that not sanitation canal, absorption pit has principles and ways of working together with the absorption well, just have a dimension / small diameter (dia.maks = 0.20 cm by 0.50 cm depth) with a distance / interval meeting. More meetings will further enhance its function.

Concluding
Maintenance of watershed conditions occur because well-managed river flow, especially supported by social institution maintains a balance between public interests and individuals. Society has realized that by planting trees of economic value on the sidelines of the agricultural system means they have to maintain watershed because the trees are able to maintain the stability of hillsides and resist the loss of land due to erosion and water flow.

Successes of the community in managing the landscape of a watershed are influencing by the following factors that interact with each other:

1.   Population (and livestock) and how they interact, including their interaction with local government. For example, if they have the customary rules and whether traditional rules still apply in their daily lives

2.    System of land use or land cover types may take the form of natural forests, logged forests, crops, economic valuable trees, grassland and forage planted embankment, roads and footpaths as well as housing

3.    Soil conditions, such as soil density, the closing level of the soil by the litter layer, soil organisms and plant roots play a role in maintaining the structure of soil compaction

4.    Topography and geology of land associated with the steepness of the slope, evidence of ground movement, the history of geology, earthquakes and volcano eruption, the balance between soil formation and erosion

5.    Climate and weather-related patterns of rainfall and season, the daily cycle of sunlight and rainfall intensity (rain, drizzle), river flow patterns that follow the pattern of rocks and hills. The presence or absence 'meandering' (formation curve of the river), which causes sedimentation of soil which probably originated from erosion and landslides, which are considered damaging in the past, but ultimately became a fertile land.

In solving management, problems of Water Resources and Water Resources Conservation efforts must exist in an integrated cooperation between different disciplines such as political science, conservation, forestry, regional planning, land, geography, geology, and hydrology. Each of these disciplines must co-exist and cannot stand-alone. Integrated cooperation needed to understand the strengths of each discipline of science, and understand the knowledge and perception of the public and policy makers in looking at and addressing the problems in managing the landscape. For that open communication between stakeholders (researchers / scientists, community and government / policy makers), need to maintained and enhanced.

Keywords : forest, forest function, conservation, water resources, watershed, river, hydrology, rainfall, rainwater