SMALL WATERSHE‘DS Thesis for the Degree of M. S. MICHIGAN STATE UNIVERSITY CLIFF R. SEPPAN EN 1970' ' amomc av 1“ ;. If - x mm; a. SIIIIS' Ir. ‘ am mum mc. :‘ LIBRARY BINDERS I Li'llllflfll’. IIOIISAR :4 Q: ,7 5:, 1 ABSTRACT SMALL WATERSHEDS By Cliff R. Seppanen Small watershed parameters are evaluated for their contributions toward a realistic definition of small water- sheds. Hydrologic performance is selected as reflecting all the parameters in a working definition. The scope, results, applicability, deficiencies, and problems of small watershed research are examined. Small watershed hydrology is compared to that of large watersheds, and five general approaches for estimating runoff are evaluated. Policy formation is reviewed in terms of political maneuvering and citizen action. Basic water rights and.water laws are traced. The special problems of urban watersheds are dis- cussed. And, the financing of, deficiencies in, incentives for, objectives and methodology of, and the responsibilities for planning, developing, and managing small watersheds are studied as means for implementing policy. SMALL WATERSHEDS By Clifford R. Seppanen A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Resource Development 1970 TABLE OF CONTENTS Introduction Chapter Chapter 2: A Chapter Chapter Chapter Chapter Chapter Identifying the Small Watershed Small Watershed Research Small Watershed Hydrology Politics and the Small Watershed Small Watershed Planning Small Watershed Development and Management Summary List of References General References 11 Page Page Page Page Page Page Page Page Page Page 12 26 58 64 76 90 93 94 INTRODUCTION Consider the small watershed. It is probably the most thoroughly researched, the most widely written about, and the most closely observed unit in water resources, which is logical since the small watershed forms the foundation of water re- source development. Individually, small watersheds generate the surface runoff and ground water supplies that feed rivers and streams; collectively, small watersheds make up the major and minor river basins, each contributing its unique charac- teristics to the aggregate of basin resources. Any change in small watershed conditions effects a proportional change in the river basin regimen. As an object of experimentation and research, the small watershed has been studied in depth; it has been surveyed, photographed, gaged, calibrated, synthesized, modeled, burned, denuded, eroded, plowed with and against the grain, sodded, cropped, reforested, paved, and even held pristine. It has been legislated upon. Yet, despite this massive research endeavor, the small watershed remains the unknown quantity in water resource development. The range in performance and in water yield and in response to treatment is as infinite and as unpredictable as the causal variables. Consequently, the small watershed defies sweeping, all-inclusive general- izations and all but the simplest of categorizations. 1 2 As an instrument in the decision-making process, the small watershed is curiously neglected. Considering that it bears the brunt of the research drive, that it has a pro- pensity for public action at the local level, and that it has a susceptibility to management practices, the small watershed is conspicuously absent from the broad policy and planning spectrum. The recent emphasis on comprehensive planning threatens to completely subordinate small water- sheds. This induced identity crisis leads to a needlessly fragmented, haphazard, and sometimes negative approach to small watershed activity. To review current thinking on small watershed problems and to compile pertinent guidelines for policy makers, planners, designers, and administrators, four categories were set up for study: identification, research, hydrology, and policy, the latter category covering politics, planning, development, and management. These categories are highly inter-related and cannot be completely isolated. This results in a degree of repetition in order to maintain continuity. Attempting a comprehensive review precludes in-depth discussions on any given topic. In studying small watersheds, several disciplines are encountered where specific references to small watersheds are not made in the literature, although the subject matter is relevant to small watershed work. The water quality and waste disposal phases of research, national politics and legislation, water law, water rights, and comprehensive 3 planning are topics embracing general principles that can be applied to small watersheds. CHAPTER 1 IDENTIFYING THE SMALL WATERSHED The initial problem encountered in studying small watersheds is defining and identifying the subject. Apparently, everyone knows intuitively how to describe a small watershed: it is - well, you know, a small water- shed. The term seems self-explanatory, and has become so commonplace that few authors go beyond titling their work as something dealing with small watersheds and throwing out an acreage in their introductory remarks to substantiate this usage. Under this format, the small watershed is difficult to pin down. For example, PA 566 of 1954 sets the upper limits of a small watershed at 250,000 acres. The American Society of Civil Engineers defines small basins as drainage areas of up to 128,000 acres in extent.1 The U. S. Bureau of Public Roads limits the small watershed to a more modest 20,000 5 acres.2 Wisler and Brater suggest 6,400 acres. The Soil 1ASCE, fiydrology Handbook, 200 2U. S. Department of Commerce, Peak Rates 9§_Runoff from Small Watersheds, 28 3C. 0. Wisler and E. F. Brater, fiydrology, 248 4 5 Conservation Service has reduced the small watershed to a mere 2,000 acres.4 If a small watershed covers 2,000 acres, it cannot also extend over 20,000 acres, or 128,000 acres, or 250,000 acres. Arbitrarily setting a limiting acreage on small watersheds has muddied rather than clarified the waters. What, then, is a small watershed? At what point does the small watershed become a river basin? (If the PA 566 criteria is adopted, more than 25 river basins in Michigan are technically small watersheds.) How do you recognize a small watershed? An adequate small watershed definition should satisfy a number of conditions: it should be uni- versally applicable; it should be phrased in easily measured and understood watershed parameters; it should be flexible enough to incorporate new research discoveries; it should be sufficiently concrete for ready inclusion in legislative measures; and it should be logically derived rather than randomly adopted. Current small watershed definitions were formulated to meet the needs of the agency adopting them. The inevitable results of this approach are unrealistic and confusing variations within a single definitive parameter. Watershed parameters fall into two major classes: natural and cultural. Under natural parameters, geometry, geology, and geography are the main subdivisions. Cultural parameters can be loosely broken down into land use, political 4U. S. Department of Agriculture, A_Method for Estimating ~m‘m— 6 subdivisions, ownership, and special interests. Most small watershed definitions try to incorporate one or more of these parameters. Size, the most easily determined of a watershed's natural features, does not provide a reliable working defini- tion. The other parameters, both natural and cultural, will be briefly examined for their definitive potential. Geographic features are altitude, latitude and longitude (or location), and orientation. Climate is a function of the geographic parameters. These factors play an important role in determining the hydrologic behavior of a watershed. They are easily established, but they are rigidly fixed, and with the possible exception of weather modification, they cannot be managed. Geographic parameters are not descriptive enough to base a small watershed definition on. Another grouping of geographic features is found in surface features: soil and vegetative cover. These are readily observed parameters, but unlike the stable features of size, location, and orientation, surface features may change over night due to natural or cultural causes. Further- more, the range of surface features on a given watershed may vary from bare rock to dense forest cover and attempting to describe small watersheds using this parameter would reduce small watersheds to even smaller mini-watersheds. Geologic features include such diverse items as under- lying strata, surface formations (hills, valleys, outcrops) glaciation history, and surface and underground drainage patterns. The first problem with using these parameters in smai the: 7 small watershed definitions is the difficulty in determining them. Nor are these parameters flexible. Barring cataclys- mic upheavals, geologic features change with the excruciating slowness of the natural erosion processes. Geologic param- eters may be consistent throughout a drainage basin or may vary drastically on a few-acre tract. Their variability and undeterminability render them unsuitable for defining param- eters. Taken together or singly, natural watershed parameters are generally descriptive, subject to precise delineation, and easily measured. Most natural parameters are readily identified and understood by the general public. 0n the other hand, consistency and universal applicability are not assured. Reliable correlation among the various parameters is unlikely and meaningful statistical comparisons would require a complex reduction-to-common-factors system. The second broad category of watershed characteristics, cultural parameters, are those man has superimposed upon the natural features, creating, for all practical purposes, artificial watersheds. In contrast to the well-defined and stable natural parameters, the cultural categories tend to be capricious and often imaginary aids to functional opera- tions: political boundaries, administrative districts, real estate subdivisions, and planning units. Cultural features may be logical, practical, and even :necessary conveniences, but each governing agency, each rmanager, each subdivider, and each planner is free to draw 8 his own boundaries subject only to local restrictions which vary from township to township, from county to county, and from region to region. A typical drainage district map shows the absurdity of defining a watershed in political adminis- tration or surveying terms. Water cannot respect political boundaries; the only imaginary lines it observes are contours. Cultural features may also be studied through land-use patterns. Under this system, watersheds may be wild, rural, suburban, or urban. A wild watershed is one that has escaped man's handiwork, except for his infrequent trespasses for his recreational pursuits like hunting or hiking. Rural water- sheds are wild watersheds that have been tamed for forestry, agriculture, or organized recreation. They are sparsely pop- ulated, yet show the marked effects of man's presence: clearing and building. The suburban watershed retains some natural features but these are rapidly being eradicated by the process of urbanization. The urban watershed, except for an occasional park, has lost any resemblance to its wild cousin. It is densely populated, paved, and polluted. The degree of watershed deterioration in the form of urbanization can be established visually from aerial photographs or in the field. But land use, aside from its cataloging function, is not an adequate parameter for identifying a small watershed. Ownership, like land use, can better be used for describ- ing rather than for delineating the extent of small watersheds. An entire watershed may be owned by an individual and held for private use. Private ownership might differentiate a 9 small watershed from a river basin as it is unlikely that a single owner would acquire an entire basin, but there is no guarantee that a small watershed will be individually owned; it may be held by the government as a part of the public domain or as state or national forests or parks. Watersheds may also be under corporate or municipal ownership but the most likely case for both large and small watersheds is a conglomerate of owners representing all three classes. Special interests are responsible for most watershed activity, and the extent of the watershed involved will vary with the activity. A watershed for upstream conservation protection or stabilization works would be much smaller than the watershed involved in a downstream flood control project. Likewise, there are optimum.watershed sizes for developing and managing which will be independent of natural parameters. In all probability, such watershed areas will conform to political boundaries. Special interest groups will seek to maximize certain watershed parameters to the exclusion of others. The problem with defining a watershed in special interest terms is that they are mutually exclusive and the limits for one group's needs would be restrictive to another group. Under the special interest format, a watershed could be defined to include a certain area, a specific soil type, a predetermined population, or any number of variables, none of which are sufficient for defining a small watershed. Cultural watershed parameters provide no better defini- tive base than do the natural parameters. They are useful for 10 descriptive or inventory purposes. They are subject to change at will and while such changes might substantially change the watershed's behavior, the parameters themselves are too ambig- uous and too arbitrary to be satisfactory for defining small watersheds. The only remaining alternative for defining a small water- shed lies in its performance or its function. Definitions can be phrased in terms of how a watershed reacts to changing con- ditions. The primary watershed function is water production; in this sense, the watershed becomes a catchment area and a hydrologic performance parameter is suggested. Many hydrolo- gists consider a small watershed to be one on which the runoff characteristics and the resulting hydrograph are determined by overland flow rather than by flow in the river channel. Seemingly simple, this definition actually integrates most of the natural and cultural parameters previously rejected as being non-definitive in themselves. Runoff is determined to various degrees by watershed size, location, geology, surface features, land use, season, and precipitation. Hydrographs, in turn, are derived from runoff. Consequently, a hydrologic definition subtly includes both natural and cultural parameters. It can be universally applied without complicated adjustments to the independent variables. The end result - performance - is the limiting factor. There are problems with a hydrologic definition, however. It is not as definite as might be desired for legislative use. Determining a hydrograph is not a task for the layman; it is 11 a technical problem that requires both hydrologic expertise and engineering judgment. It requires a detailed description of the watershed, and it is helpful, but not necessary, to have hydrologic measurements on rainfall and stream flow. Yet, in spite of these somewhat rigorous requirements, hydrologic performance is the most effective method for separating small watersheds from large watersheds and river basins. CHAPTER 2 SMALL WATERSHED RESEARCH Realistic watershed development and management is de- pendent upon realistic watershed research. Research can provide pertinent background data that is essential for plan- ning. It is not sufficient to have an accurate description of a watershed. The most thorough tabulation of watershed parameters remains a mere inventory without the related re- search results required to establish performance predictions based on the complex interactions of the parameters. Research should be conducted to fill the gaps in the knowledge of watershed parameters and their functions. Water- shed research can be justified only if a new and widely appli- cable truth is discovered or if an accepted dogma is either reconfirmed or refuted. In order to accumulate meaningful results, the complete physical make-up of a watershed should be understood and the watershed should be completely instru- mented in order to chart all water movement and storage. Finally, research should study quality aspects in their historical and environmental connotations. The thrust of most past research has been on sampling Specific watersheds, then superimposing the results on 12 wa‘ pa. ho 15 watersheds having reasonably similar climatic and physiographic parameters. No matter how similar two watersheds may seem, however, each will have individual conditions and problems which are not duplicated and therefore cannot be legitimately studied on another watershed. The ultimate objective of research in surface water hydrology is an understanding of the physical processes in- volved in the phenomenon of runoff from the time the raindrop hits the surface of the ground to the time it is available for use. Hydrologic research shares with other segments of water- shed activities a joint interest in precipitation, water use, infiltration, aquifer recharge, water quality, and flood flows. Research in surface water hydrology supplies data for the designers and operators of systems controlling, utilizing, or disposing of surface water. The principal stimulus for hydro- logic research is in the continued expressed need of those engaged in water resources work. In reviewing past research reports, the most successful watershed research in terms of predictive applicability and reliability appears to be that which relates structural or land-use techniques to reducing sedimentation. Measurements on stream loads before and after conservation practices are installed are easily and reliably measured. The cause and effect relationships are directly tied together without being influenced to any appreciable extent by watershed parameters. The effects of applying similar conservation measures to changing peak discharges are not so easily determined. 14 When the research effort turns from quality to quantity, all the uncertainties and vagrancies of the hydrologic cycle are encountered. Measuring the effects of watershed management on water yield, for which peak discharge is an upper envelope, involves the combined effects of precipitation, soil moisture content, season, soil structure, geology, solar energy, ground water levels, and climatic conditions, all of which are more significant in determining water yield than are conservation measures. A third area of research delving into land-use changes has been evaluating the downstream effects of upstream protective works. Here, the dominant role is taken by such factors as channel storage, overland flow, surface detention, drainage density, basin geometry, and the storm pattern, while surface measures have only a minor influence on runoff or on downstream flooding potential. It is difficult to outline the sphere of influence of a watershed as watersheds are not self- contained entities and what is done to one will affect the adjacent watersheds. Just how far downstream the consequences of management on a given watershed can be carried has not been established by research. To complicate matters, all the variables listed under water yield investigations are active in and must be considered in evaluating upstream - downstream relationships. Water-related problems center about man - his knowledge, or lack of it, his institutions, and his objectives. Most watershed research has studied the water resources rather than 15 the role these resources play in the socio-economic system. Granted, the study of water resources cannot employ traditional economic analysis because of valuation problems, institutional constraints and uncertainty. A group of economists working under Kneese have attacked the economic problem but there has been virtually no research attempt to correlate the signifi- cant systems of organized social action dealing with water resource development and management with the dynamics and interactions of these systems. As the demands upon a fixed water supply increase, an understanding of the mechanics of social systems is going to be vital in securing adjustments in water uses. In surface water hydrology, three areas that should be considered as high-priority research areas are: studies of stochastic hydrology, applied research needed to provide reliable and practical methods of extending observed data to encompass the variability existing in hydrologic events, and methods to develop synthetic hydrology for the many areas where hydrologic measurements are not available. The aggre- gate investment in small structural works far exceeds the cost of the major water developments. Of particular need in small watershed research is a means for generalizing stream flow records and for better methods of analyzing and present- ing results. Ephemeral streams are often the only source of water supply in arid and semi-arid watersheds. Research must develop general relationships for estimating runoff, water losses, and recharge in these regions. 16 Neglected areas in watershed research, in addition to surface-water hydrology, include ground water research, water quality research, the socio-economic spectrum, the patterns of precipitation that produce small-area floods, and understanding the thermodynamics of the hydrologic cycle. But the most glaring research gap is in the field of urban hydrology where until a year or two ago there was simply no research being done. The direction of research on small experimental water- sheds has been toward agriculture, forestry, and wilderness preservation, none of which are remotely related to urban watersheds whose streams are little more than open (or en- closed) sewers, and whose open spaces are vast impervious seas of asphalt and concrete. In April of 1969, the American Society of Civil Engineers published ”Basic Information Needs in Urban Hydrology,” which with its 1968 predecessor, ”Urban Water Resources Research,” identifies the major problems in urban hydrology and recommends studies and research projects for their solution. Among the salient recommendations were: all aspects of water resources research should be prosecuted concurrently with provisions for ample inter-communication and feed-back; the need for a national research program directed by a central body to stimulate, co- ordinate, and undertake urban water resources research; the acquisition of rainfall-runoff-quality data should be started as soon as possible to develop inputs suitable both for future use and for current management and operation of water works; and existing mathematical models for simulating the rainfall- runoff dated, instai of ab: devel. rainf. data I T9310 17 runoff-quality process should be continually tested and up- dated, starting with the meager data now available. The recommended research plan begins with several pilot installations for measuring hydrologic events on catchments of about 50 acres in size being set up concurrently with model development and the analysis of time and space variations of rainfall. Subsequent phases include establishing a national data collection network, setting up regional models, defining regional storm patterns, developing storm drainage criteria for planning, design, and operation of facilities, and pro- viding guidelines for local jurisdictions for operating existing facilities. Under this research format, potential benefits can be obtained in the comprehensive, multi-purpose develop- ment of urban water on a scale greater than that realized for river basins. Water and Metropolitan Man, a research conference co- sponsored by the Engineering Foundation and the American Society of Civil Engineers in August of 1968 listed eleven areas where urban research was needed: in communications, planning, social impact, management, legal and institutional aspects, regulation, data needs, precipitation, detention storage, design problems, and systems analysis. Among the most critical research needs are determined efforts to find means and ways to link engineering systems to social systems in research designs. The goal is to learn how elements of engineering systems affect, relate to, or interact *with.elements of the social system. Research collaboration 18 between social scientists and engineers should be directed to the following questions and needs: 1. How legal systems relate to and affect both engineer- ing and social systems. 2. A rigorous definition of the responsibilities of each segment of the public and private decision making arenas. 3. Ways to consolidate water resource administration. 4. Criteria for preserving engineering, safety, and aesthetic values. 5. An understanding of motivating mechanisms. To accomplish this, research will have to more clearly define concepts, words, and terms, so they are mutually understand- able by social scientists, engineers, and other members of the urban water resources team. Water quality has become a pressing national concern. Rapidly expanding populations require more of everything - especially of good water. The greater the urbanization of a region, the more pronounced is the interdependence of water supply and waste disposal with the ironic results that local water fronts become blighted, forcing municipalities to seek water supplies from.more distant sources as Detroit has had to do. The quality of water is influenced by usage, natural pollution, urban and agricultural drainage, solid waste dis- ‘posal practices, recreational activities, and even political implementations. To date, most water quality research has been directed toward determining whether or not water can be 19 made suitable for use at a reasonable cost. It seems that the research focus depends upon whether pollution by waste disposal is imposing an external cost on subsequent users, or is interfering with the optimum use of water resources, or is threatening the well-being of certain groups. A survey of current water quality research indicates that deficiencies exist in: 1. improving treatment processes . translating theory to design . optimizing water quality management 2 5 4. developing stream use criteria 5. ground water quality management 6. improving marine disposal systems 7. storm drainage water quality As is the case with most resources, accepted methods of exploitation are not questioned until a crisis - shortage, low quality or whatever - arises. Water research is seldom directed to revolutionary concepts while tried methods seem to be work- ing. This is especially true in water quality where waterborne waste disposal has been accepted as a fact of life. Only when the public raises an outcry are researchers prompted into seek- ing remedial alternatives. As an illustration of this public apathy problem, the February 23, 1970 edition of Newsweek carried an article on New York's Dead Sea, the site of the Metropolitan New York Sewage Treatment Plant's sewage sludge dumping grounds for the past 40 years. Suddenly, New Yorkers realized that they had 20 a 20 square mile problem area 12 miles offshore. Why? The dumpings were beginning to wash up on their sandy beaches. No one was concerned that the dumpings had smothered seaweed and other vegetation on the ocean floor, or that fish in the area are afflicted with fin rot, or that mollusks taken within six miles of the dumping ground are unfit to eat, except for ecologists who are worried about the enormous quantities of wastes being dumped into the oceans. The Sandy Hook Marine Laboratory in New Jersey, after a fifteen month study, con- cluded that if waste disposal were stopped immediately, it would take at least ten years for the dead sea to regenerate itself. This situation does have research implications: waste disposal is of concern for small watersheds as well as for metropolitan areas. Other methods of waste disposal are little better than dumping at sea. Incineration pollutes the air. Converting sludge to fertilizer is not economically successful. Clearly, research must develop an improved basis for designing and implementing economical, esthetic and environ- mentally safe methods of waste disposal, or if complete pol- lution abatement is preferred, research must develop practical new waste-handling techniques. Considering that about 70 percent of precipitation is lost to evapotranspiration, there has been little creative research in this area. Research has tried to measure how many inches of water plant A transpires annually, or how much water is lost per square inch of leaf surface area when the need is for research on managing precipitation in areas as diverse as 21 weather modification, breeding plants that conserve water, the effects of chemically treating plants and their growing mediums to retard water losses, the timing of water applica- tions, and, of course, continuing the most studied facet of evapotranspiration, land-use management. Recent trends in watershed research have seen economic analysis become an integral element in the search for optimum water utilization; cross-disciplinary research become the rule rather than the exception; new disciplines developed using computers and requiring precise definitions, clear and accurate determinations of relationships, and specific quantitative data; an increased emphasis on recreation, water quality, and management of water-related land uses; the recognition of political, administrative, and institutional factors as signi- ficant causal forces, though the agencies which allocate water resources and protect their quality need more research atten- tion; and a redefining of federal, state, and local roles as exemplified in the Water Resources Research Act of 1964. Studies of political and financial structures; engineer- ing problems and solutions; legal constraints, encouragements, and deficiencies; operational and maintenance requirements, and the time required to produce results through successfully implemented urban water resource plans should be undertaken to identify the common ingredients that can be used to expedite all phases of water resource activity. Last, but not least, there is a need for increasing the number of skilled profession- als trained to carry on the research effort outlined above. 22 How is a research watershed selected? To begin with, the research team must have a research plan outlining their goals. Watershed selection will depend upon many things: the type of data to be obtained, the anticipated duration of the research project, the accessibility of the site, the ease of installing measuring devices, the ease of altering watershed parameters for study, and watershed stability, to name a few. To maintain control over research watersheds, the research plan should provide for avoiding unexpected ownership changes during the study period. Other guides for selecting research watersheds suggest that geology and soils should be as uniform as possible, not merely related, and that a single land-use or management practice should prevail throughout the watershed. There are two types of research watersheds: experimental watersheds and representative watersheds. The essential dif- ference in the two are the end results of the research effort. The experimental watershed is chosen and instrumented to study hydrologic phenomena - rainfall or runoff. 0n the other hand, a representative watershed is just what its name implies: a watershed chosen and instrumented to represent all watersheds with similar features instead of making measurements on every watershed. Experimental watershed research is aimed at discov- ering significant principles, relationships, and factors that can be incorporated in prediction schemes, helping to answer such questions as what will be the peak runoff from a water- shed and how often can such a discharge be expected to occur? With representative watershed research, data is collected 25 which can be applied more or less directly to watersheds where the data in question can not practically be gathered. Watershed research is undertaken by many organizations, but these organizations can be loosely grouped into four cat- egories. Government agencies, educational institutions, cor- porations, and foundations, and private groups or individuals may conduct or sponsor research. Many colleges and univer- sities maintain experimental stations for watershed research. Notable are Utah State University at Logan, the University of Illinois at Urbana, and Colorado State University at Fort Collins. The United States Geological Survey, the Bureau of Reclamation, the Soil Conservation Service, and the Army Corps of Engineers are a few of the federal agencies that both conduct and finance research. Various foundations and professional societies provide scholarships and research grants, in addition ‘to providing official organs for publishing research results. lflgtgg Resources Research, published by the American Geophysical Union, the Journal of; the Irrigation Ed Drainage Division of the American Society of Civil Engineers, the American Lager liesources Bulletin, the Journal 9§_Forestgy, and Agricultural gaggineering are several publications that carry research arti-