Edwin D. Ongley

Flocculation of suspended sediment in rivers of southeastern Canada

Abstract Flocculation has been studied extensively within marine science and sanitary engineering and the controlling processes are generally well known. Less research, however, has focused on flocculation within the freshwater river environment. Consequently the occurrence, importance and controlling mechanisms are poorly understood. We examine the suspended sediment characteristics of six rivers in southeastern Canada in order to determine the nature and significance of flocculation in finegrained suspended sediment transport and the factors that may influence it. While flocs may not always comprise the majority of particles in transport, they always represent more than 90% of the total volume of sediment transported. Independent variables that may influence flocculation, such as temperature, pH, major ions, dissolved and particulate organic carbon, suspended solids concentration and bacteria were measured in conjunction with floc size for one of the rivers. Particulate organic carbon concentration, suspended solids concentration and attached bacteria may be important controlling factors of riverine flocculation.

The state of suspended sediment in the freshwater fluvial environment: a method of analysis

Abstract Primary particles in rivers are frequently and perhaps characteristically transported as larger flocculated particles. Typically floc size has been determined by destructive, indirect laboratory methods or by laborious microscopic measurements. A unique direct observation digitizing method of floc characteristic analysis was developed and applied to suspended solids from Sixteen-Mile Creek in Southern Ontario. Suspended sediment particles in the creek are strongly flocculated, and the flocs are relatively stable within the realms of the sampling and analytical method. The digitizing method allowed for direct observation of floc structures which is impossible with conventional methods of sediment sizing. The method provides reasonable results with good precision on floc equivalent spherical diameter, surface area, perimeter and circularity. It is limited, however, by its labour intensive nature, possibility of sediment overlap, the individual investigators criteria and by the photographic and microscopic instruments and techniques used. Other sizing techniques, or the use of the digitizing method by other investigators, may produce different results.

Application of continuous flow centrifugation to contaminant analysis of suspended sediment in fluvial systems

Abstract Suitability of continuous‐flow centrifugation for bulk recovery of suspended sediment for biogeochemical purposes is reviewed. Centrifuge recovery characteristics and efficiencies in a variety of rivers and for different regimes are presented. The observed distribution of organochlorine residues amongst water, aquatic plants and suspended sediments demonstrate the necessity for standardized bulk collection protocol for suspended sediment.

Transjurisdictional Water Pollution Management in China: The Legal and Institutional Framework

Abstract Transjurisdictional water pollution is a major technical and legal problem for the Chinese government and arises from the many problems in the current legal, institutional, and operational framework for water resources and for water environment, planning, and management. The law for pollution and the water law must be seen within the context of the current transition in China from the traditional “rule by law” to “rule of law.” Nevertheless, the common view in China is that each law gives “power” to the State Environmental Protection Administration (SEPA) for pollution and the Ministry of Water Resources (MWR) for water quantity management. The administrative framework is described, and the role of local government is highlighted as a major reason for failures in enforcing environmental laws. River basin organizations have little administrative power except for flood emergencies and are not mandated to manage river basins in a holistic context. We outline a variety of deficiencies and recommend corrective actions in the Water Pollution Prevention and Control (WPPC) Law. These include such issues as a lack of definition of terminology, an inadequate definition of pollution, a lack of trans-boundary water quality standards, problems of administrative transparency, access to data and information, and several technical issues that cause friction between the two ministries. At the highest level, there is need for a permanent inter-ministerial coordination arrangement to deal with the harmonization of laws, institutional arrangements and operational practices between SEPA and MWR.

REDESIGN AND MODERNIZATION OF THE MEXICAN WATER QUALITY MONITORING NETWORK

ABSTRACT Mexico is a large developing country, much of which is arid and semiarid. With a population of more than 81 million, Mexico is confronted with growing water scarcity and serious pollution of much of its surface water The National Water Commission (Comision Nacional del Agua—CNA) has embarked on a major program of modernization of water management. The water quality program, now consisting of 564 surface water stations (plus 239 groundwater stations), has no strategic design, has major data gaps, is not representative of important areas, is often unreliable, does not contain data for many current issues such as organic contaminants, and suffers from out-of-date or lack of facilities. Because the existing network is not representative of the range of issues for which data are needed, network redesign began from first principles rather than as an optimization of the existing network. The new program is built around client needs, and uses four components—a primary network of some 200 stations that ar...

Transjurisdictional Water Pollution Management: The Huai River Example

Abstract Transjurisdictional water pollution has been a major problem for Chinese authorities due to legal, institutional, and procedural frameworks that are inadequate to deal with integrated water resources management or for resolving local and inter-provincial disputes. The pollution crisis in 1994 in the Huai River was of such severity that the State Council directly intervened and promulgated new legal and institutional approaches to deal with this transjurisdictional crisis. This included a new regulation with new procedures, new institutional arrangements, and specific measures to deal with polluters. The Huai River example provides a background for how transjurisdictional pollution might be managed elsewhere in China and on the continuing problems in Chinese transjurisdictional pollution management. The example of the Huai River basin demonstrates typical problems of environmental governance in China and illustrates the directions that the Chinese Government is taking to resolve these.

Non-Point Source Water Pollution in China: Current Status and Future Prospects

Abstract The pollution impacts of different types of non-point source pollution (NSP) were identified on a large scale in the lower Great Lakes of North America in the 1970s, beginning with the eutrophication crisis in these lakes and subsequently expanding to toxic substances and endocrine disrupting substances. Since then, there has developed a large knowledge base on this subject. Especially in the United States, there is now an extensive legislative and administrative framework for non-point pollution management and control. Recently, China has recognized that non-point source pollution is a major contributing factor to water pollution in many parts of China. There has been recent work in several of the large lakes of China where eutrophication is severe. Elsewhere, factory farms contribute large pollutant loads. There are currently limited legal, administrative, or technical frameworks for evaluating or controlling non-point source pollution in China. As part of the reform of governance in China, the State Environmental Protection Administration (SEPA) is examining the need for a legislative and operational framework to ensure that non-point source pollution is adequately evaluated within the larger context of water pollution control measures and to ensure appropriate cost efficiencies in pollution control investments. The overall status and legal framework for non-point source pollution control in China is examined in this paper. Parallels between China of today and North America of the 1970s are instructive for policy makers in China.

Vertical and lateral distribution of fine-grained particulates in prairie and cordilleran rivers: Sampling implications for water quality programs

The fine sediment fraction, usually <63 μm, is generally regarded as significant for water quality issues. This fraction is usually presumed to be evenly distributed in the vertical column. Using period of record data for three prairie rivers and three cordilleran river sites, and midstream data from the Mackenzie River, we examine the degree to which near-surface samples of silt and clay are representative of the vertical and cross section. These data are available only for high flow conditions. Surface samples of silt + clay tend to underestimate the vertical mean concentration by less than 10%; also, 89% of the surface data at five of the six sampled sites are within ±15% of the vertical mean concentration. The individual vertical distributions of clay and silt display inconsistent and variable patterns of concentration with depth and can include large excursions within individual profiles. Our data do not indicate that large, deep rivers behave differently from shallow ones. There is no evidence of increasing homogenization of silt + clay across the section as discharge increases. The data indicate typical errors that may be expected if surface samples are used to characterize the water column at high discharges. A theoretical basis for the observations is provided together with a discussion of assumptions which render theory imprecise for fine-grained cohesive sediment.

Transjurisdictional Water Pollution Disputes and Measures of Resolution: Examples from the Yellow River Basin, China

Abstract Transjurisdictional water pollution problems are increasing in number and are becoming a significant governance problem in China. A large number of transjurisdictional water pollution disputes that have far-reaching social effects are occurring between provinces and are also frequent between municipalities, counties, towns, and villages. In this paper, several transjurisdictional water pollution cases in China, particularly in the Yellow River Basin, are discussed. The problems and causes for transjurisdictional water pollution are addressed. There are many causes for transjurisdictional water pollution problems although the key reasons are the rapid economic development, the failure of local authorities to enforce the existing laws and to implement administrative decisions, as well as inadequacies in the legal framework. Other factors include poor technology, shortage of funds, the institutional division of jurisdiction and management over water quantity and quality both administratively and legally, the lack of transparency in the decision-making process, insufficient public participation and information disclosure, poor communication, and lack of involvement of stakeholders in basin or sub-basin organizations.