Sediment Transport and Process of Sedimentation

Sediment transport is the phenomenon of movement of solid particles primarily due to movement of the fluid in which the sediment is entrained and force of gravity acting on the sediment. The fluid can be air, water, ice or volcanic fluid. Understanding of the engineering and ecological aspects from sources to final settlement of the phenomenon is becoming more and more important for many reasons, some of them includes

• Analyzing the after effects of dam flushing and ecological response to this in downstream dams and connected sea.
• Devising dam’s optimal operational routine to minimize sediment accumulation in the reservoir, which reduces the storage capacity
• Creation of more realistic and useful models to understand what would happens under a certain set of conditions or changes at a specific place
• Finding environmental reasons of increased dust storms and desertification in some areas of world

Sediment transport due to water motion occurs in rivers, the oceans, lakes, seas, and other water bodies. Process of settling down of carried sediments normally due to low velocity of water is called sedimentation. The magnitude of problem can be assessed by the fact that total storage capacity of all dams on earth today is about 6000 Km3 (according to WWF)and  Prof. K. Mehmood estimated in 1986 that average loss of storage annually due to sedimentation is about 50 Km3. This makes about slightly less than 1 % annual storage loss. During my master thesis, which was about modeling sediment transport on Tenryu River, upstream of Sakuma Dam, I spent some time on thinking about solution of sedimentation. As if we can be able to resolve it, we will not only get upfront saving when we spend millions on sediment removal every year, but will also have reliable long-term storage capacity.
There are various techniques developed to compensate the problem somehow including dam flushing, dredging, controlling sediment inflow from source etc. I personally think that there is no match of ' control from source' but at the same time it requires highly skillful planning and coordination between many stakeholder making it more challenging. Some other quick solutions of sedimentation problems came in my mind but since for now these are only pop-thoughts, scientific evidences needs to establish before digging further.

1. Exploiting chemical properties of sediments...

That is, at least theoretically, to make such an environment in which
Incoming sediments would change their chemical composition and dissolve into water which would prevent there settling
Incoming sediments breakdown and become so thin that all or most of incoming sediments become wash load and pass through dam without settling.

2. Artificial ecological system...

At least theoretically, a system can be produced in which there could some living organism, which would eat, and digest incoming sediments and their raw material produced is unsettle-able. I have read somewhere that there are planktonic animals eating floating debris in Lake Baikal, which help it to maintain its clarity. So these planktonic can be genetically researched to absorb or eat more debris or and sediments to make deposited sediments to a low level.

3. Use of Nano Technology .....

This would in principle works similar to Ecological system. That is, desirable amount of self-sustained nano robots can be spread in problematic water bodies where these nano robots would break down sediments either chemically or physically so that these become almost permanently suspended/well mixed.

As I already mentioned these are merely  pop-thoughts and so far non scientific. However I am sharing them just to have a second opinion about them. Or may be you just have a comment about what you think or know if somebody somewhere is working on similar things.

Purpose of Sediment Transport Studies

Even with progression of science and technology, sediment transport remains a phenomenon that is not fully comprehended. Numerical modeling is a common method to analyze sediment transport and subsequent bathymetric changes. This helps in gaining an insight into the prospective behavior of sediment transport, which provides a background for policy making. Among several of benefits of such studies may include estimation of possible expenditure in coming years, to take out deposited sediments and estimation of the dam life to serve its planned purposes.

Englebright Dam and reservoir, looking north.  (Courtesy of USGS)

Integrated Water Resource Management (IWRM) – Basic Concept

The basic idea behind the concept of IWRM is that fresh water is a scarce entity and all different uses of fresh water are all different uses of it are all competing and interdependent. And while this evident to all of us, so far not proper attention has been paid to it. Some of examples of its mutual-dependent uses are

·      High demand for irrigation purposes of fresh water mean that there will less water left for Industrial  and Drinking purposes

·      If contaminated wastewater from municipalities and industries is allowed to be flow out into main river system unattended and untreated, it will harmful for the fisheries, ecosystem and biodiversity.

·      And if the water is protected and retained for fisheries and biodiversity the less can diverted for other purposes like irrigation.

·      A dam or other water retaining structure is very useful for collecting and distributing water as and when required for irrigation purposes, controls flooding and can be used for power generation. While on the other hand it increases water logging at upstream, harmful for that particular river system’s unique biodiversity. And if the water is stored in rivers, very less water is the end of river flows are almost dried up resulting saline sea water intrusion into delta land.

So examples are many and they all prove that all different water uses unregulated use of scarce water resources is extremely wasteful and unsustainable. That use may give a temporary or short term benefit for one purpose but may also produce much more danger to somewhere else.

So in IWRM, Integrated means that all different uses of water resources are to be considered together. And water allocations and management decisions should account for an overall sociological and economical goals and also include the sustainable development. And a coherent policy making related to all sectors needs to be existed. One of the way to achieve this integrated policy and decision making is to involve all user groups (e.g. farmer, household users, industrialists etc.) in water resource management from initiation of policy making till the management. And from national level to grass root level. And by this way we will get many additional benefits such as, informed users apply local self regulations related to issues such as water conservation and catchment protection far more effectively than central regulation and surveillance can achieve.

Management is used in a more broader sense, And means that we must only just to focus on day to day management of water resources. But we must consciously manage water development in a ways that ensures long terms sustainable use even for future generations. And that we must left the plant in even better state  for our new generations  to come so that also get benefited from its resources  as we are now.

And as defined by Cap-Net “Integrated Water Resources Management is therefore a systematic process for the sustainable development, allocation and monitoring of water resources use in the context of social economic and environmental objectives.” And it further says implies that “It contrast with sectoral approach that applies in many countries.” Like where responsibility of drinking water rests with one agency, for irrigation with another and for the environment yet another, lack of cross –sectoral linkages leads to uncoordinated water resources development and management. And this is  what results in disputed and unsustainable system.

European Union’s Water protection and management (Water Framework Directive)

The Water Framework Directive (more formally the Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy) is a European Union directive which commits European Union member states to achieve good qualitative and quantitative status of all water bodies (including near shores’ marine waters) by 2015. It is a framework in the sense that it prescribes steps to reach the common goal rather than adopting the more traditional limit value approach.

The directive defines 'surface water status' as the general expression of the status of a body of surface water, determined by the poorer of its ecological status and its chemical status. Thus, to achieve 'good surface water status' both the ecological status and the chemical status of a surface water body need to be at least 'good'. Ecological status refers to the quality of the structure and functioning of aquatic ecosystems of the surface waters. Water is an important facet of all life and the water framework directive sets standards which ensure the safe access of this resource.

The Directive requires the production of a number of key documents over six year planning cycles. Most important among these is the River Basin Management Plans, to be published in 2009, 2015 and 2021. Draft River Basin Management Plans are published for consultation at least one year prior.

Good ecological status is defined locally as being lower than a theoretical reference point of pristine conditions, i.e. in the absence of anthropogenic influence. Article 14 of the directive requires member states "to encourage the active involvement of interested parties" in the implementation of the directive. This is generally acknowledged to be an assimilation of the Aarhus Convention

ACT

Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy

Summary

The European Union (EC) has established a framework for the protection of:

inland surface waters *;

groundwater *;

transitional waters *; and

and coastal waters *.

This Framework-Directive has a number of objectives, such as preventing and reducing pollution, promoting sustainable water usage, environmental protection, improving aquatic ecosystems and mitigating the effects of floods and droughts.

Its ultimate objective is to achieve “good ecological and chemical status” for all Community waters by 2015.

Administrative arrangements

Member States have to identify all the river basins * lying within their national territory and to assign them to individual river basin districts *. River basins covering the territory of more than one Member State will be assigned to an international river basin district.

Member States are to designate a competent authority for the application of the rules provided for in this Framework-Directive within each river basin district.

Identification and analysis of waters

·         By 2004 at the latest, each Member State shall produce:

·         an analysis of the characteristics of each river basin district;

·         a review of the impact of human activity on water;

·         an economic analysis of water use;

·         a register of areas requiring special protection;

·         a survey of all bodies of water used for abstracting water for human consumption and producing more than 10 m³ per day or serving more than 50 persons.

This analysis must be revised in 2013 and every six years thereafter.

Management plans and programmes of measures

In 2009, nine years after the Framework-Directive entered into force, management plans were produced for each river basin district, taking account of the results of the analyses and studies carried out. These plans cover the period 2009-2015. They shall be revised in 2015 and then every six years thereafter.

The management plans must be implemented in 2012. They aim to:

• prevent deterioration, enhance and restore bodies of surface water, achieve good chemical and ecological status of such water by 2015 at the latest and to reduce pollution from discharges and emissions of hazardous substances;
• protect, enhance and restore the status of all bodies of groundwater, prevent the pollution and deterioration of groundwater, and ensure a balance between groundwater abstraction and replenishment;
• preserve protected areas.

The management plans for river basin districts can be complemented by more detailed management programmes and plans for a sub-basin, a sector or a particular type of water.

Temporary deterioration of bodies of water is not in breach of the requirements of this Framework-Directive if it is the result of circumstances which are exceptional or could not reasonably have been foreseen and which are due to an accident, natural causes or force majeure.

Member States shall encourage participation by all stakeholders in the implementation of this Framework-Directive, specifically with regard to the management plans for river basin districts. Projects from the management plans must be submitted to public consultation for at least 6 months.

From 2010, Member States must ensure that water pricing policies provide adequate incentives for users to use water resources efficiently and that the various economic sectors contribute to the recovery of the costs of water services, including those relating to the environment and resources.

Member States must introduce arrangements to ensure that effective, proportionate and dissuasive penalties are imposed in the event of breaches of the provisions of this Framework Directive.

A list of priority substances selected from among the ones which present a significant risk to the aquatic environment has been drawn up at European level. This list is set out in Annex X to this Framework-Directive.

Reference (below mentioned linkes as retrived on January 09, 2011)

1. http://en.wikipedia.org/wiki/Water_Framework_Directive
2. http://europa.eu/legislation_summaries/agriculture/environment/l28002b_en.htm
3. http://ec.europa.eu/environment/water/water-framework/info/intro_en.htm

IWRM Roamap's 25 Elements - A way to Improve IWRM Process

IWRM Roadmap as explained previously is a way to judge the current status of IWRM in a River Basin. Here the same points are listed again with comments as to how to make improvement against respective element.

IWRM Element	Comments for Improvement
1. River basin organization	Build capacity in new or existing River Basin Organization (RBO), mainly focusing on four dimensions of performance (that is stakeholders, internal business process, learning and growth and financing) under the NARBO (Network of Asian River Basin Organization's service.
2. Stakeholder participation	Institutionalize the stakeholder participation in river basin planning and management process including but not limited to active participation of local governments, civil society organizations (like academia, active NGOs parliamentarians, media), and the private sector and an enabling framework for meaningful stakeholder participation in project specific and planning decisions.

Definition of IWRM

As far as definition of IWRM is concerned, each active entity has defined or more precisely expressed IWRM in its own style, which in a broader sense required the same efforts to implement and yields the same result. So it would be interesting to look at how GWP (Global Water Partnership)  EC (European Commission) and USAID defines the IWRM.

1.    GWP definition of IWRM as “A process that promotes the co-ordinated development and management of water, land and related resources, in order to maximize the resultant economic and social welfare in an equitable manner without compromising the sustainability of vital ecosystems.”

2.    And EC describes it with same meaning but with slightly different wordings “IWRM expresses the idea that water resources should be managed in a holistic way, coordinating and integrating all aspects and functions of water extraction, water control and water-related service delivery so as to bring sustainable and equitable benefit to all those, dependent on the resource (EC, 1998).”

3.    And USAID expresses it as “A participatory planning and implementation process, based on sound science, that brings stakeholders together to determine how to meet society’s long-term needs for water and coastal resources while maintaining essential ecological services and economic benefits (USAID).”

A Short Overview of Current Global Water Picture

Resources are insufficient

Currently the water resources at global scale are stressed due to over exploitation. Water demands like for agriculture, industry and domestic use are increasing day by day. One of the main reason for this urbanization and population growth.

Trends in Global Urbanization

Demand loads are exceeding the available supplies

Average renewable water : ca 2000 m3

Per person and year (Engelman, LeRoy, 1993)

Substantial part of which is used by ecosystems

Amount remained for human use: ca 1000 m3

1 000 000 L/person/year = 2740 L/person/day

Out of which:

69% is used for irrigation (- 1890 L/person/day)

23% is used by industry ( (- 630 L/person/day)

Only 8% remains for household use:

(i.e. 220 L/person/day)

Average household consumption in some areas in the world are as follows

USA: 700 L/p/day

Sweden: 200 L/p/day

Senegal: 29 L/p/day

Nomad in Sahara: 5 L/p/day

Severe Environmental/Ecological issues are severe

 Due to the incoming pollution and unplanned water activities (e.g. unplanned damming affecting natural river flows too much) at the up streams the biodiversity is depleting slowly in Mekong , Amazon and Indus river basins and  other problems like intrusion of sea water in delta ect. are resulting.

Policy and institutional issues are complicated

 Harmony in water use policies for different purposes and among different stakeholders needs to be established. The situation became even more difficult to manage in situations when one river is crossing two or more international borders.

Fragmented and Sectoral Present approach

In most of the places in world, for different uses, water is managed by different departments which sometimes have entirely different and even contradicting goals. And no harmony in the policy exists.

Available choices are highly capital demanding

 Water related structures are considered one of the costlier and time taking projects and with no immediate or near future results. Therefore a huge effort is required to establish the political will to invest in such projects.