Drainage Master Research Articles

Sewer rehabilitation planning - priority and cost planning using GIS

Rehabilitation priority and cost planning are an important and integral part of urban drainage master planning in Switzerland. Although Entsorgung + Recycling Zürich (ERZ), the sewer-age utility of the city of Zürich, has considerable financial means available for the rehabilita-tion of its sewers, it has so far not established a continuous leading role in triggering rehabili-tation projects among the city’s utilities departments, which results in a suboptimal qualitative improvement of the sewer network. This was due to organisational as well as technical rea-sons. It was thus decided in late 2003 to develop a decision support tool for rehabilitation and cost planning, which visualises the most urgent rehabilitation needs. A lot of data necessary for rehabilitation and cost planning is readily available on different databases and servers, but was so far never linked to provide a semi-automatic tool that combined all the information. This paper describes the basics and the methods for the design of a rehabilitation- and cost-planning prototype.

LOS ALAMOS FOREST FIRE IMPACT MODELING1

ABSTRACT: A controlled burn at Bandelier National Monument got out of control and burned about 43,000 acres (17,400 hectares) near Los Alamos, New Mexico, in May 2000. The wildfire caused dramatic changes in infiltration capacity and wettability of soils in many of the watersheds above Los Alamos National Laboratory (LANL) and destroyed the duff layer, dramatically reducing the interception and infiltration capacity of the formerly forested watersheds. These sudden changes in basin hydrology necessitated a rapid assessment of hydrology and hydraulics for the canyons running through LANL property to evaluate flood risk, plan emergency flood protection measures, and assess potential sediment and actinide transport. This paper presents the results of hydrologic and hydraulic modeling of Los Alamos Canyon following the wildfire. The large scale modeling effort, with over 13,000 cross sections for the hydraulic model (5,000 for Los Alamos Canyon, 8,000 for Guaje Canyon), relied heavily on a geographic information system (GIS) for model input and floodplain delineation. The HEC‐geoRAS model provided good integration between the hydraulic model (HEC‐RAS, Version 3.0.1) and the GIS (ArcView, v. 3.3). These modeling results are being used in drainage master planning efforts at LANL and in the development of sediment transport models using HEC‐6T. Sediment transport modeling results will be used to develop actinide transport models for the canyons at LANL.

Anatomy of a ‘fossil’ landslide from the Pleistocene of SE Spain

Pleistocene landslide failures are rarely recorded in the literature due to difficulties in recognition in the field. An adaptation of standard landslide classification based on activity is used to identify and examine the significance of a ‘fossil’ Pleistocene landslide from the Mocatán catchment of the Sorbas Basin, SE Spain. Recognition of the landslide is based on identifying key, but subtle anomalies in the geology and drainage. The fossil landslide at Mocatán developed principally in response to a rapid increase in valley incision rates associated with capture-induced base-level changes in the master drainage. This was facilitated by the weak sand and silt lithology of the study area. The landslide was a significant morphological modifier of the environment. Holocene drainage follows the original landslide morphology, whilst more recent gullying and piping exploits planes of weakness developed within the internal body of the landslide feature. In addition, the landslide removed much of the Pleistocene divide, facilitating future river capture.

Adjustment of a drainage network to capture induced base-level change: an example from the Sorbas Basin, SE Spain

Quaternary catchments in the south of the Sorbas Basin, SE Spain have been affected by two regionally significant river captures. The river captures were triggered by changes in regional gradients associated with sustained Quaternary uplift in the region of 160 m Ma −1. The first capture occurred in the early Pleistocene and re-routed 15% of the original Sorbas Basin drainage into the Carboneras Basin to the south. The second occurred in the late Pleistocene and re-routed 73% of the original Sorbas Basin drainage to the east. This latter capture had dramatic consequences for base-level in the Sorbas Basin master drainage. Local base-level was lowered by 90 m at the capture site, 50 m at 7 km upstream and 25 m at 13 km upstream of the site. The base-level change instigated a complex re-organisation of the drainage networks in systems tributary to the master drainage over the ensuing period (some 100 ka). After the capture, drainage systems closer to the capture site experienced a tenfold increase in incision rates over most of their network. Those located some 13 km upstream of the capture site experienced a fivefold increase in incision, although in this instance, the changes do not appear to have propagated to the headwater regions of the drainage nets. The sensitivity of individual catchments was largely governed by geological controls (structure and lithology). The detailed network evolution in the most sensitive areas can be traced by reconstructing former drainage pathways using abandoned drainage cols and the alignment and degree of incision of the drainage networks. Three main stages of evolution can be identified which record the progressive spread of base-level changes from the master drainage. These are Stage 1 (pre-capture): original south-to-north consequent drainage; Stage 2 (early stage, post capture): aggressive subsequent southwest-to-northeast and east–west drainage developed along structural lineaments first in the east of the area (Stage 2a), and later in the west of the area (Stage 2b); and Stage 3 (late stage, post capture): obsequent drainage developing on the topography of the Stage 2 drainage. All stages of the network evolution are associated with drainage re-routing as a function of river capture at a variety of scales. The results highlight the complex response of the fluvial system, and the very different geomorphological histories of adjacent catchments, emphasising the need for regional approaches for examining long-term changes in fluvial systems.

Stream incision and terrace development in Frijoles Canyon, Bandelier National Monument, New Mexico, and the influence of lithology and climate

The record of stream incision and terrace development in Frijoles Canyon, NM, was investigated to examine the controls on channel evolution in this region. Frijoles Canyon developed after deposition of the voluminous ignimbrites of the Tshirege Member of the Bandelier Tuff at ca. 1.22 Ma, which provides excellent temporal constraints on canyon evolution. Base level fall along the Rio Grande, the master drainage in the region, contributed to initial incision of the stream. Development of a major knickpoint in basalt near the Rio Grande, however, has effectively isolated most of the stream channel from direct effects of this base level change since the Early or Middle Pleistocene. Late Quaternary evolution of the channel has included development of strath and fill terraces that record the effects of climatic variations and local lithologic variations within the tuff on channel processes. A fill terrace, underlain by up to 13 m of coarse gravelly alluvium, records significant aggradation in the Early to Middle Holocene following a major regional climate change. Aggradation probably resulted from large increases in sediment supply in the Holocene relative to the Late Pleistocene, which was perhaps related to variations in intense summer rains. Rapid incision in the Middle to Late Holocene has stranded the underlying strath up to 21 m above the modern channel, and local rates of incision of up to 4 m/ka are more than 10 times the average rates since 1.22 Ma. Holocene incision displays great spatial variability associated with local lithologic variations, and results in a stream profile that has evolved rapidly in the last 10,000 years. The high rates of incision occur where easily eroded nonwelded tuff is exposed in the canyon bottom, whereas a more resistant vapor-phase altered tuff unit upstream has impeded incision. Incision may also have been affected by migration of knickpoints within the tuff. Paired strath terraces record periods of local base level stability and lateral erosion that were terminated by episodes of downcutting. The downcutting was probably controlled by rare high magnitude floods capable of stripping the pervasive gravel armor and exposing nonwelded tuff beneath the stream-bed. No tectonic influence on Late Quaternary terrace development or stream incision has been recognized despite Frijoles Canyon being crossed by the Pajarito fault zone, a major bounding structure of the Rio Grande Rift. Instead, climatic influences on sediment supply and flood characteristics, mediated by lithologic variations in the canyon bottom, have controlled Late Quaternary stream profile evolution.

Impacts of urbanization on palustrine (depressional freshwater) wetlands—research and management in the Puget Sound region

This paper summarizes the results of the Puget Sound Wetlands and Stormwater Management Research Program, which examined the impacts of urban stormwater on wetlands. Results are presented for data collected between 1988 and 1995 for 19 wetlands, showing changes in wetland hydrology resulting from urban conversion and the subsequent impacts on plant and amphibian communities. The amount of watershed imperviousness, the forested area, and the degree of outlet constriction were found to be the most significant factors affecting wetland hydroperiods. As hydroperiods changed, plant communities shifted towards communities adaptable to the new hydrograph. Wetlands with water level fluctuation above 20 cm resulted in lower plant richness in the emergent and scrub-shrub zones. Similarly, wetlands with water level fluctuation greater than 20 cm were significantly more likely to have low amphibian richness of three or fewer species. A primary goal of the research program was to employ the results to improve the management of both wetlands and stormwater in urban areas. Hydrologic guidelines were applied to King County's basin planning and master drainage planning efforts. Controls that focused on minimizing impervious surfaces and maximizing forest retention in the wetland watershed proved to be the most widely usable strategy.

Badland Morphology and Evolution: Interpretation Using a Simulation Model

A drainage basin simulation model is used to interpret the morphometry and historical evolution of Mancos Shale badlands in Utah. High relief slopes in these badlands feature narrow divides and linear profiles due to threshold mass-wasting. Threshold slopes become longer in proportion to erosion rate, implying lower drainage density and higher relief. By contrast, in slowly eroding areas of low relief, both model results and observations indicate that drainage density increases with relief, suggesting control by critical shear stress. Field relationships and simulation modelling indicate that the badlands have resulted from rapid downcutting of the master drainage below an Early Wisconsin terrace to the present river level, followed by base level stability. As a result, Early Wisconsin alluvial surfaces on the shale have been dissected up to 62 m into steep badlands, and a Holocene alluvial surface is gradually replacing the badland slopes which are erocing by parallel retreat. © 1997 by John Wiley & Sons, Ltd.

Drainage Planning and Control in the Urban Environment the Singapore Experience

Singapore is situated 137 km north of the equator and is subject to heavy tropical rainstorms, particularly during the North-east monsoon season between November and January. Flooding was prevalent in the past as the older parts of the city were built on relatively low-lying areas and the drainage systems were not adequate to convey storm water runoff effectively. Rapid urbanisation in the 1970's and 1980's brought about drastic transformations of the hydrological characteristics of the drainage catchments in Singapore. More areas were paved up, resulting in increased storm water runoff being generated during heavy downpour. This paper deals with the strategies adopted by Singapore to keep the flood situation under control despite the vast extent of new land developments that are continuously taking place. It discusses the drainage master plan and the drainage development programmes that were implemented over the years for flood alleviation and prevention, including the drainage control policies being pursued by the Drainage Department as a land drainage authority. The paper also covers the integration of drainage projects with land developments to maximize land use and the creation of aesthetic waterways to enhance the urban environment.

Integrating Drainage, Water Quality, Wetlands, and Habitat in a Planned Community Development

This paper describes the planning, design, and construction of multiuse drainage facilities for the Rock Creek development, a planned residential community in the town of Superior, located between Denver and Boulder, Colorado. The Master Drainage Plan provides for a regional system of storm-water channels and detention facilities that provide management of the increased runoff due to urbanization and multiple use of the channels and ponds for open space, recreational greenway corridors, wetland preservation, and riparian habitat. Rock Creek is also the first community in Colorado to implement a comprehensive plan for quality enhancement of urban storm-water runoff. Under the plan, all storm flows from the development are routed through specially designed extended detention basins prior to discharge into the receiving drainageway. Selected stabilization measures are used along the channels to preserve their natural character and maintain stability.

Integrated approach to the point-non point-pollution abatement in urban drainage

An area in Switzerland of 260 km2 with 230 000 inhabitants was analysed for the feasibility of combined sewage overflow (CSO) tanks to reduce the pollution in receiving waters during rain events. The case study demonstrates the consideration of the point and of the non point pollution with respect to choice and application of water pollution control measures in urban drainage. For example, measures which reduce pollutant sources (e.g. substitution of phosphorus in detergents) or reduce surface runoff (e.g. dispersed retention or infiltration of rainfall runoff) are more efficient than a strategy of uniform and area wide application of CSO tanks. The new Swiss guideline for Integrated Urban Drainage Master Planning (IUDMP) introduces a radical changes in the scope and in the procedures of planning process. This guideline defines the urban drainage system as one single system, consisting of urban area, soil and ground water system, drainage network, waste water treatment plant and receiving waters. The consideration of comprehensive urban drainage system allows the choice of site-specific and problem-related measures.

Integrated approach to the point-non point-pollution abatement in urban drainage

An area in Switzerland of 260 km2 with 230 000 inhabitants was analysed for the feasibility of combined sewage overflow (CSO) tanks to reduce the pollution in receiving waters during rain events. The case study demonstrates the consideration of the point and of the non point pollution with respect to choice and application of water pollution control measures in urban drainage. For example, measures which reduce pollutant sources (e.g. substitution of phosphorus in detergents) or reduce surface runoff (e.g. dispersed retention or infiltration of rainfall runoff) are more efficient than a strategy of uniform and area wide application of CSO tanks. The new Swiss guideline for Integrated Urban Drainage Master Planning (IUDMP) introduces a radical changes in the scope and in the procedures of planning process. This guideline defines the urban drainage system as one single system, consististing of urban area, soil and ground water system, drainage network, waste water treatment plant and receiving waters. The consideration of comprehensive urban drainage system allows the choice of site-specific and problem-related measures.

Improvement in the selection of design storms for the new master drainage plan of Barcelona

In 1988 Barcelona finished its Master Drainage Plan, where a modified Chicago storm of 10 years return period was used. Nowadays, a new Master Drainage Plan has started due to enormous urbanistic changes with the Olympics, the increasing concern for CSO problems, etc. For this Plan the use of a 67 year record from an intensity raingauge, and long-term simulation models allows a change in the traditional concept of design storms, working with historical storms. In spite of that, the complexity of the urban drainage system of Barcelona advises the use of design storms for predesign purposes. Because of that, a study has been carried out to select new design storms to solve the problem that the Chicago storm is too unfavourable as it has all its maximum medium intensities corresponding to a 10-year return period, which is not realistic.

Improvement in the selection of design storms for the new master drainage plan of Barcelona

In 1988 Barcelona finished its Master Drainage Plan, where a modified Chicago storm of 10 years return period was used. Nowadays, a new Master Drainage Plan has started due to enormous urbanistic changes with the Olympics, the increasing concern for CSO problems, etc. For this Plan the use of a 67 year record from an intensity raingauge, and long-term simulation models allows a change in the traditional concept of design storms, working with historical storms. In spite of that, the complexity of the urban drainage system of Barcelona advises the use of design storms for predesign purposes. Because of that, a study has been carried out to select new design storms to solve the problem that the Chicago storm is too unfavourable as it has all its maximum medium intensities corresponding to a 10-year return period, which is not realistic.

FLOODPLAIN STORAGE AND LAND USE ANALYSIS AT THE WOODLANDS, TEXAS1

ABSTRACT: The Woodlands, a totally planned community north of Houston, Texas, was studied in detail in an effort to develop a master drainage plan which minimizes adverse impact on the 100‐year floodplain. A total of 40 HEC‐1 and HEC‐2 computer runs were made to evaluate various development, channelization, and reservoir storage options.

Estimating Design Flows for Urban Drainage

As an area urbanizes, peak runoff tends to increase. But the effects of urbanization on storm flows can be offset by a policy of requiring detention storage. A new method for computing design flows and storage volumes has been developed to prepare a master drainage plan for a municipality in Western Canada. The method involves use of a hydrologic model to analyze all the significant storms of record over the range of parameter values likely to apply in the area, a frequency analysis of the computed peaks, storage of the results in a large matrix in a computer, and subsequent interpolation of the stored data. By inputting estimated values of the parameters for any particular basin, the user can obtain peak flows for any desired return period and also the amount of detention storage required. Parameters can be specified either with single values or by ranges, taking into account parameter uncertainty.

Agricultural Drainage Water as a Basis for Wildlife Development in the San Joaquin Valley of California

ABSTRACT IMPORTANT marshland habitat in California is estimated at 1.94 million ha (4.8 million acres) with State and Federal ownership totaling about 93,555 ha (231,000 acres). Some of the habitat area has a partial water supply, some a full supply, but much of it has very little water. Agricultural drainage could provide a full water supply for up to 127,170 ha (314,000 acres) of wildlife habitat by the year 2000. The impact of such usage would be greatly beneficial both to wildlife habitat development and to irrigated cropland. Agricultural drain-age can provide a firm water supply for wildlife and the wildlife use will allow the development of on-farm drainage systems to maintain land productivity. Further, such a short-term plan would be easily adaptable and in fact complementary to a long term plan for a master drainage system to be implemented at a later date.