cultural ditches as related to quality protection and introduce the papers in this special section oftheJournal ofSoil and TM1ter Conservation. Papers include reviews on phosphorus (P), nitrogen (N), soil for­ mation, and biogeochemistry in ditches; Improved management of agricultural original research on fundamental processes operating in ditches; and methodologies and drainage ditches for water quality case studies of innovative ditch manage­ ment practices. It is our hope that this special protection: An overview section will provide a fundamental resource to scientists, practitioners, and policy mak­ B.A. Needelman, P.j.A. Kleinman, j.5. Strock, and A.L. Allen ers working to improve ditch management for increased agricultural efficiency and Abstract: Agricultural drainage ditches are essential for the removal of surface and ground environmental quality. water to allow for crop production in poorly drained agricultural landscapes. Ditches also mediate the flow ofpollutants from agroecosystems to downstream water bodies. This paper The Science of Drainage Ditches provides an overview of the science, management, and policy of ditches. Ditches provide a Hydrology. The essential function of ditches unique opportunity to address nonpoint source problems from due to is to prevent flooding through the rapid the concentration of the contaminants and the engineered nature of ditch systems. A bet­ removal of surface water during storm and ter understanding of the nature of these complex system and the technologies available and snowmelt events and to lower the water table under development to improve their management will assist in the design and implementa­ during and between events to prevent crop tion ofwater quality protection programs. stress and to allow field soils to dry such that they may be driven upon and worked with Key words: -channelized -drainage ditches-water quality agronomic equipment. Drainage ditches function within general systems of land drainage that have been reviewed exten­ sively elsewhere (see Skaggs and Schilfgaarde Artificial drainage and ditchingare essen­ The ITlanagement of agricultural ditches has 1999; Skaggs et al. 2005a). In this issue,Vadas tial for crop production in many areas of historically focused on water conveyance et al. (2007) discuss the importance of lat­ the United States, either for direct land and management; there is increased interest eral subsurface flow in supplying stormflow drainage or as conduits for tile drain and to improve management for envirOllillen­ to shallow ditches. In the general drainage effluent. Ditches are unique tal quality benefits related to water quality, conununity, researchers and practitioners are ecosystems in that they integrate charac­ habitat, diversity, and emissions. working to develop and implement systems teristics of streams and wetlands. Some Humans have long used open-air of drainage water management to improve ditches are straightened streams with ­ ditches for land drainage, including ditch­ water quality protection with methods such bottom sediments while others are inter­ ing in Mesopotamia around 9000 BP (van as water-control structures within tile drains mittent wetlands with perennial vegetation Schilfgaarde 1971) and the Egyptians and to promote denitrification within field soils throughout the ditch bottom (figure 1) and Greeks around 2400 BP (Shirmohammadi et (Skaggs et al. 1994, 2005b) and in-ground thick accumulations of soil organic matter. al. 1995).The Long Marsh ditch in 1789 was bioreactors for N reduction. Ditches range in size from small depressed the first recorded ditch project in Maryland. Chemistry. The chemistry ofditch systems channels designed primarily to carry surface By the early 20th century, land drainage was is complex with dissolved, colloidal, and par­ runoffto major channelized streams draining a large-scale endeavor involving state and ticulate materials interacting within soils, large watersheds and regional groundwater. federal partnerships focused primarily on the sediments, and organisms through chemical Because of their engineered nature, ditches removal of surface water and groundwater. and biogeochemical pathways. In this issue, do not follow natural fluvial networks, though Ditches are extensive in the Midwest, irri­ mechanisms of fluvial geomorphology do gated lands in California, and the Atlantic Brian A. Needelman is an assistant professor function to shape ditches. Coastal Plain. Over two million acres in at the University of Maryland, College Park, Ditches serve as primary conduits for North Carolina are affected by and Maryland. Peter J.A. IUeinman is a soil sci­ drainage and therefore carry pollutants ditch drainage. In Indiana, there are over entist at the Pasture Systems and Watershed from agroecosystems to downstream water 36,000 ullies of public ditches (McCall and Management Research Unit, USDA Agricultural Research Service, University Park, Pennsylvania. bodies. Ditches also function to control Knox 1979). In Maryland, there are over Jeffrey S. Strock is an associate professor at water tables in the landscape, influencing 821 nllies of publicly administered drain­ the Southwest Research and Outreach Center, landscape hydrologic, chemical, and bio­ age ditches and hundreds of ullies more of University of Minnesota, Lamberton, Minne­ logical processes, and serve as active zones privately managed ditches (Mister 2006). sota. Arthur L. Allen is an associate professor of chemical and biological activity to trans­ In this paper, we provide an overview of at the University of Maryland Eastern Shore, form, emit, and retain various pollutants. the science, management, and policy ofagri- Princess Anne, Maryland.

JULY IAUGUST 2007 VOLUME 62, NUMBER 4 ~ Figure 1 Vegetated ditch in Minnesota. aquatic and wetland habitat across landscapes, including many that wouldn't otherwise have these habitats. Ditch vegetation spe­ cies composition within ditch bottoms and along banks is affected by soil and water table characteristics (van Strien et al. 1989; Pierce et al. 2007), ditch structure (Bouldin et al. 2004), grazing (van Strien et al. 1989), nutl·i­ ent inputs (van Strien et al. 1989; Portielje and Roijackers 1995), ditch m.anagement (van Strien et al. 1991) and eutrophication status Ganse 1998;Janse andVan Puijenbroek 1998). Pierce et al. (2007) present results from a greenhouse study on the response to flooding of Leersia oryzoides (rice cutgrass), a conunon plant in agricultural ditches. They found that flooding did not negatively affect plant productivity unless it led to extended soil oxygen depletion. Macroinvertebrates are diverse and active in m.any ditch systems and may be use­ ful as indicators of ditch environmental quality (Karr and Chu 1999; Davis et al. 2003; Langheinrich et al. 2004). Macroinvertebrates function to m.ediate carbon and nutrient a variety of reviews on the cycling of par­ These reviews underscore opportunities for cycles through organic matter decomposition ticular elelTlents are provided, including N improved management of ditches to protect and shredding. Bioturbation by macroinver­ (Strock et al. 2007), P (Sharpley et al. 2007), water quality. tebrates such as crayfish Inay serve to cycle and iron and sulfur (Needelman et al. 2007). Biology and Ecology. Ditches provide nutrients between surficial and subsurface layers and provide rapid flow pathways within ditch sediments and soils (figure 2) (Needelman et al. 2007). Figure 2 Algae are abundant in many drainage Crayfish exposed by a ditch-dredging operation on the Coastal Plain of Maryland. ditches, particularly those rich in nutrients (figure 3). Algae may be important for ditch nutrient cycles, removing nutrients from ditch and returning carbon and nutri­ ents to ditch sediments and soils upon loss of inundation in a ditch. Kleimnan et al. (2007) provide evidence that algae in ditches nuy contribute to the loss of particulate P frolTl ditches during storm events. Geomorphology and Pedology. Ditches are present within a specific geomorphological setting that will affect their physical, chemical, and biological functions. The composition of the ditch bottom and bank materials following excavation is dependent on the nature ofthese materials; they will be altered with tilne under the contrasting hydrologic and biogeochemical processes operating in the ditch systeITI. The fluvial geomorphol­ ogy of ditches differs froITI that of natural flow channels because ditches are dredged and straightened, thereby increasing chan­ nel capacity and gradient (Simon 2006). This n'lay result in increases in bed mate-

1]2 JOURNAL OF SOIL AND WATER CONSERVATION Figure 3 Abundant algal growth in standing water of a ditch. mean losses oftotal P from [\'110 ditches drain­ ing nonpoint sources averaged 13.9 kg ha-' yr-', with single year losses as high as 26.2 kg ha-'. Very little of this P derived from over­ land flow from adjacent fields «4% of total P) (figure 4), pointing to subsmface flows, ditch soils, and potentially mats of algae as important sources of P. Ditches likely play a role in moderat­ ing downstream P losses via processes of hyporheic exchange (Nguyen and Sukias 2002). Research by Dunne et al. (2007) and Vaughan et al. (2007) confirms that ditch soils can serve as large stores of P, particularly in intensively managed systems where significant amounts of P have been land applied. Dunne et al. (2007) exam..ined ditch soil P characteristics under several land uses in Florida. In that study, unimproved pasture ditch soils had lower contents oftotal P, water-extractable P, and Mehlich-l P than did ditch soils fi·om dairies and improved pastures. Vaughan et al. (2007) observed large variability in P concentrations within Maryland ditches, highlighting the role rial discharge, causing upstream degradation, and mechanisms are involved in N cycling of spatial variability in ditch soil P. Their downstrean"l aggradation, and bank instabili­ dynamics and transport pathways in ditches research revealed that materials accumulating ties along ditches and connected tributaries. including N mineralization, nitrification, and within ditch channels can have substantial Degradation will occur under increased peak denitrification (Strock et al. 2007). Not sur­ sorption capacities and therefore should not discharge or channel gradient. Channel inci­ prisingly, ditches draining agricultural fields be discounted as buffers for dissolved P. sion and widening are dominant forms of can transport large amounts ofN. Schmidt et The studies of Sharpley et al. (2007) and ditch degradation that may result in sub­ al. (2007) monitored seven ditches draining Smith and Pappas (2007) provide insight stantial sediment yield increases compared to soils with a long history of receiving poul­ into the role ofbed materials (soils and sedi­ stable systems. Some ditches, particularly in try litter. They found that shallow ditches ments) in controlling P losses. Sharpley et al. low-relief landscapes, undergo an aggrada­ «0.6 m [<2 ft]) served primarily as con­ (2007) found that soils in Maryland ditches tional response, eventually reaching stability duits for surface water, with most ditches draining agricultural areas maintained higher due to insufficient transport capacity relative exporting N at rates of 5.1 to 15.5 kg N dissolved reactive P (DRP) concentration in to loadings. ha-' yc' (4.6 to 13.8 lb N ac' yr-'). One flowing water than did soils from a ditch in Needelman et al. (2007) discuss the shallow ditch had an annual loss of 43.5 kg a forested area. Differences were consistent role that processes of soil formation have N ha-' (38.8 lb N ac'), corresponding with with relative concentrations of Mehlich-3 in water quality in some ditches. When likely contributions from point sources that P and equilibrium P concentration at zero the sediments and underlying soil materi­ included poultry barns and a litter storage sorption (EPCo) of the ditch soils. When als in ditches are stable, they may become facility. Ditch management, in conjunc­ ditch soils were exposed to simulated run­ young soils and thereby are able to support tion with other agronomic, ecological, and off water rich in DRp, ditch soils served to vegetation and may form soil horizons engineering approaches to mitigating non­ remove P fi·om the flowing water, with P through processes such as organic matter point source pollution, offers land managers uptake by the soils related to a soil's P sorp­ accumulation, structure formation, faunal opportunities for reducing N export from tion maximum and clay content. M..icrobial activity, and biogeochemical transformations artificially drained agroecosystems. inunobilization appeared to account for up ofiron and sulfur. Phosphorus. A growing body of research to 40% ofP uptake. now exists on the function of ditches to Sediment. Ditches serve as a conduit for Drainage Ditches and Water Quality mediate the transport of agricultural P. As sediment, even in low-relief landscapes. Nitrogen. Considerable research exists on conduits for point and nonpoint sources of Sediment is a significant water pollutant the £1te of agricultural N in relationship to P, ditches can yield loads that are of envi­ and it also carries particulate-bound nutri­ artificial drainage (e.g., Skaggs et al. 2005b). romnental concern. Kleinman et al. (2007) ents and other contaminants. Sediment Ditches often have high concentrations of monitored ditches draining Coastal Plain transported through ditches is derived from N and, compared with other water courses, soils that had received more than 20 years particulates in surface water and groundwa­ tend to be N-saturated. Numerous processes of poultry litter application. Over five years, ter inputs and from the and failure of

I JULY I AUGUST 2007 VOLUME 62, NUMBER 4 . GU - Figure If Ditch and field runoff monitoring at the University of Maryland Eastern Shore research farm on the Coastal Plain of Maryland. ing stagnant/flowing water regime. Ditches may emit and influence the landscape-scale emission of greenhouse gases such as nitrous oxide and methane. The emission of nitrous oxide is discussed by Strock et al. (2007). Minkkinen and Laine (2006) observed that methane emissions £i'om ditches were influ­ ence by vegetative community and water level in a drained forested peatland; however, in a follow-up study it was found that the emissions from ditches were not sufficient to change landscape-scale estimates (Minkkinen et al. 1997).

Management of Drainage Ditches In-Ditch Practices. Ditches require man­ agement to maintain hydraulic function including vegetation maintenance and clean­ outs or dredging if sediment accumulation restricts flow. There are a variety of addi­ tional ditch management practices that can improve water quality, provide habitat, and improve water management for agricultural production. The Maryland Department of Agriculture has developed and field-tested a "weed wiper," a tool to selectively apply ditch banks. Sediment may undergo repeated the United States (Bush et al. 2004;Vaughan to woody vegetation in ditches cycles ofdeposition and resuspension within et al. forthcoming). When sulfides oxidize, instead of the conU110n practices of mowing ditch networks.Vegetation and organic mat­ they produce acidity, which has been associ­ and broad applications (Rhoderick ter accumulation provide a means to entrain ated with fish kills and other environmental et al. 2006).With this technology, nonwoody and stabilize sediment (Needelman et al. problems. However, monosulfides have also vegetation is maintained to retain sediment, 2007); disruption of these materials through been documented in ditches in landscapes stabilize soils and banks, and provide ecosys­ ditch maintenance, such as a clean-out, may without acid sulfate soils (Needehnan et al. tem habitat.Woody vegetation is removed to make the ditch system susceptible to greater 2007), indicating sufficiently anaerobic con­ maintain flow capacity and prevent serious sediment losses. An effective means to con­ ditions to reduce sulfur. The sulfur source in blockages after dislodgement. trol downstream sediment losses is to provide agricultural systems may be animal manures Smith and Pappas (2007; also see Smith floodplain areas for ditches, either within the or agrochemical inputs (Vaughan et al. et al. 2006) quantified differences in the channel itself (Powell et al. 2007a, 2007b) or forthcoming) . cycling of nutrients and herbicides from within an adjacent floodplain (Evans et al. Other Contaminants and Emissions. Illinois ditch sediments representing dredged 2007). Ditches also serve as conduits for other con­ and pre-dredged conditions (figure 5). Carbon. Many ditches have a higher net taminants such as heavy metals, pesticides, Sediments were packed in and primary productivity than streams due to pathogens, and pharmaceuticals (Cooper exposed to a regime of recirculating flows the presence of vegetation and high algal et al. 2004; Bennet et al. 2005). The unique that exposed them to varying concentra­ growth due to eutrophication and periods of characteristics of ditches may lead to high tions of N (NH4-N, N03-N), dissolved P, stagnation. This organic matter may become retention and transformation rates of many and herbicides (atrazine, glyphosate). Due a source of biological oxygen demand if contaminants. Pappas and Smith (2007) found to stratification of ditch sediment proper­ transported downstream. Soil organic matter that sediments exposed by dredging had a ties, sediments exposed to ditch flow prior accumulation in some ditches represents a reduced capacity to remove the herbicides to dredging were able to remove more N, P, significant contrast from most fluvial systems. atrazine, metolacWor, and glyphosate than and glyphosate from the water column than This organic matter accumulation occurs did the sediments present prior to dredging. did sediments representing the bed material under low flow conditions, which prevents The biofilms developed on ditch soil and after dredging. Under these circumstances, scouring and depresses decomposition rates sediment smfaces and vegetation may play Smith and Pappas (2007) suggest that dredg­ under anaerobic conditions (Needehnan et an important role in pathogen interception ing be conducted during periods of the year al.2007). and removal (Stott and Tanner 2005). Crum when contaminant loads are expected to be Acidity. The formation of monosulfides et al. (1998) found that the disappearance of low and that producers should minimize P has been documented in ditches draining the herbicide Linuron was slowed at cooler applications during and inU11ediately after acid sulfate soil landscapes in Australia and temperatures in ditches with an alternat- dredging.

174 JOURNAL OF SOIL AND WATER CONSERVATION Figure 5 Ditch dredging or "clean out" operation. watershed experiment to test the role of water-control structures. Over the first year after a water-control structure was installed in one of the t\¥o ditches, the total-N load was similar for the t\¥o ditches. However, analysis of nonstorm event samples indi­ cated a greater decline in N concentration in flow from the ditch with the water-con­ trol structure, with total-N concentrations up to 71% lower than observed in the ditch that was not equipped with a water-control structure. Opportunities also exist to deploy water-control structures in conjunction with "bioreactors" or "biological curtains" that provide sources of organic matter under reducing conditions to convert nitrate-N to gaseous forms ofN (Schmidt et al. 2007). Given the growing concern of P losses from ditches, novel nLanagen'lent practices are being developed to curtail the transfers of dissolved forms of P, which are not targeted by traditional management practices such as dredging and drainage management (flow control). Penn et al. (2007) review the poten­ tial to use P-sorbing materials in drainage The installation ofwater-control structures moting denitrification (figure 6) (Gilliam ditches to sequester dissolved P from ditch is a conunon means to retain plant-avail­ et al. 1979; Evans et al. 2007). Strock et al. water. They describe an array of traditional able water within the agricultural landscape (2007) describe preliminary findings from agronomic amendments, water treatment while decreasing pollutant losses and pro- t\¥0 Minnesota ditches used in a paired materials, and industrial byproducts that can serve to convert dissolved P in ditch water to insoluble forms. A variety ofapproaches exist Figure 6 to using P-sorbing materials in ditches such as Water-control structure raising the water table to near the soil surface. broadcasting to ditch soils, dosing ditch effiu­ ent with dissolved compounds, and routing ditch water through structures that contain solid materials. Preliminary evidence from an experimental structure designed to treat effiuent from a small ditch indicates a high potential for P removal and similar potential to remove other pollutants of concern such as arsenic, copper, nickel, and zinc. Powell et al. (2007a, 2007b) provide and test an approach to size agricultural ditches with a two-stage channel: a sediment under­ lain channel designed for flow conveyance surrounded by a vegetated bench that evolves as a floodplain due to overbank accretion (figure 7) (Jayakaran and Ward 2007). While more expensive to construct than traditional ditch channels, t\¥o-stage channels require less long-term maintenance and provide the ecosystem services of sediment entrain­ ment and habitat improvement (Powell et al. 2007b). Evans et al. (2007) describe t\¥o alternate in-ditch management practices: the establish­ ment of in-stream wetlands and the redesign

I JULY I AUGUST 2 007 VOLUME 62, NUMBER 4 GU - Figure 7 Natural benches formed in a drainage ditch. order to reduce the nutrient enrichm.ent of water bodies, protect agai11St , and enhance wildlife habitat (Agricultural Drainage Managem.ent Coalition 2007). State. The ownership and management of ditches varies by state in the United States. In Maryland, most larger ditches are owned and maintained by Public Drainage Associations and Public Watershed Associations (Mister 2006). The associations are governed by elected managers and include annual mem­ ber meetings. Landowners benefiting fium drainage are taxed; funds are used for ditch operation and maintenance. The Maryland Department of Agriculture has the respon­ sibility to regulate and oversee the drainage and watershed associations and conduct annual walking inventories in conjunction with ditch managers, leading to formal oper­ ation and maintenance plans. Cost-sharing assistance for ditch best management prac­ tice (BMP) implementation is made available in part through United States Environmental Protection Agency Section 319 grants. The first comprehensive drainage law of channels using natural design principles. The Policy of Drainage Ditches in Minnesota was passed in 1887. Under In-stream wetlands have been found as an National. At a national level, drainage ditch Minnesota drainage law (Helland 1998), gen­ effective means to mitigate nonpoint source policy generally falls within the broader cat­ eral authority for public drainage is vested in N pollution (Hunt et al. 1999). egory of drainage management (Carman individual counties, although some drainage External Ditch Practices. Several manage­ 2006). Federally, many ditch-related pro­ system.s are located in and under the supervi­ ment practices are available for installation grams are administered by the USDA. sion of a watershed district. Minnesota law adjacent to ditches to provide a variety of Cost-share assistance program are gen­ requires a permanent grass buffer on each ecosystem services. Most ditches are discon­ erally administered through the USDA side of a new ditch or when improvements nected from their natural floodplains, and Natural Resources Conservation Service are made to an existing ditch. The law also therefore during large flows transported (NRCS) such as the Environmental Quality stipulates that environmental criteria must sediment is not deposited. Eva11S et al. (2007) Incentives Program, the C011Servation be considered when considering a proposed describe a practice applied in North Carolina Security Program, the Plain Easement drainage project. Recently, some groups where the floodplain surrounding a ditch Program, the Farmland Protection Program, have expressed interest in modernizing the is lowered, thereby reconnecting it to the and the Wetlands Reserve Program. The drainage law. ditch net\¥ork.The establishment ofriparian USDA Farm Service Agency administers Evans et al. (2007) discuss the role of buffer zones and wetlands around ditches is the Conservation Reserve Program. and drainage districts and water management an option to reduce pollutant inputs by pro­ the Conservation Buffer Initiative. The service districts in North Carolina. Both of viding a zone of remediation for overland USDA NRCS National Engineering Field these programs provide for the establishment, and subsmface flow (Evans et al. 2007). Handbook (available online at www.info. taxation, and governance ofdrainage system. Ditch Conversion Projects. Ditch segments usda.gov/CED/) includes chapters on Water management service districts provide may be restored to wetland or floodplain water table control, wetland restoration, and greater flexibility than drainage districts in systems in order to improve water quality drainage management. that they allow for multiple objectives, such and provide wildlife habitat. The Delaware The Agricultural Drainage Management as water quality improvement, while a drain­ Department of Natural Resources and SystemsTask Force is a USDA technical work age district is restricted to the objective of Environmental Control is monitoring a con­ group addressing water management issues drainage and flood protection. version of a ditch to a riparian wetland to on agriculturally drained lands (Agricultural determine the effectiveness of the system. at Drainage Management Systems Task Force Summary and Conclusions treating agricultural runoff (Barthelmeh and 2007). Collaborators include federal, aca­ Ditches are unique engineered ecosystems Biddle 2006). In Maryland, a series ofditches demic, and private members.TheAgricultural with characteristics of streams and wetlands. were converted to wetlands to offset wetlands Drainage Management Coalition is an orga­ There is growing interest in the improve­ disturbed during state highway construction nization of private companies working to ment of ditch management to mitigate the Gellick 2006; Mister 2006). promote drainage water management in loss of pollutants from agroecosystems to

JOURNAL OF SOIL AND WATER CONSERVATION o ~------downstream water bodies while increas­ Carman, D. 2006. Federal prograrns and ditch management. Minkkinen, K., and J. Laine. 2006. Vegetation heteroge­ ing agricultural efficiency. Optimal design III Improved Management of Agricultural Drainage neity and ditches create spatial variability in methane Ditches for Water Quality Protection: Field Tour of ditch management practices will require fluxes from peatlands drained for forestry. Plant and Soil Guide, ed. B.A. Needehnan and S.A. Wills. College 285:289-302. continued advances in the understanding Park, MD: University of Maryland. www.sawgal.umd. Minkkinen, K, J. Laine, H. Nykanen, and PJ. Martikainen. of the ecological, chemical, and hydrologi­ edu/DrainageDitches/2006_tourandsymposium/. 1997. Importance of drainage ditches in emissions of cal processes operating within ditches and Cooper, CM., M.T Moore, E.R. Bennett, S. Smith Jr.,J.L. methane from nures drained in forestry. Canadian Farris, CD. Milam, and ED. Shields Jr. 2004. Innovative their surrounding landscapes. Application of Journal of Forest Research 27:949-952. uses of vegetated drainage ditches for reducing agricul­ Mister, D. 2006. Public drainage in Maryland. III Improved innovative methods to treat and remove pol­ tural runoff. Water Science and Technology 49:117:123. Management of Agricultural Drainage Ditches for lutants frOITl ditches may prove instrumental Crum, SJ.H., G.H. Aalderink, and TCM. Brock. 1998. Water Quality Protection: Field Tour Guide, ed. B.A. for the achievement of watershed manage­ Fate of the herbicide linuron in outdoor experimental Needelman and S.A. Wills. W\V\v.savlgal.umd.edu/ ment objectives. ditches. Chemosphere 36:2175-2190. DrainageDitchesI2006_tourandsymposium/. College Davis, S., S.W Golladay, G. Vellidis, and CM. Pringle. Park, MD: University of Maryland. 2003. Macroinvertebrate biomoniroring in intermittent Needelman, B.A., D.E. Ruppert, and R.E. Vaughan. 2007. Acknowledgements coastal plain streams impacted by animal agriculture. The role ofditch soil formation and redox biogeochem­ Support for the 2006 Ditch Project Field Tour and Journal ofEnvironmental Quality 32:1036-1043. istry in nutigating nutrient and pollutant losses from Symposium was provided, in part, by funding through the Dunne, EJ., K.A. McKee, M.W Clark, S. Grunwald, and agriculture. Journal of Soil and Water Conservation USDA Cooperative State Research,Education, and Extension K.R. Reddy. 2007. Phosphorus in agricultural ditch soil 62(4):207-215. Service National Imegrared Water Quality Program award and potential implications for water quality. journal of Nguyen, L., and J. Sukias. 2002. Phosphorus fractions and number 2003-51130-02109 and a gram from the Keith Soil and Water Conservation 62(4):244-252. retention in drainage ditch sediments receiving surface Campbell Foundation for the Environment. We are par­ Evans, R.O., K.L. Bass, M.R. Burchell, R.D. Hinson, R. runoff and subsurface drainage from agriculmral catch­ ticularly gratefitl to the following individuals who oversaw johnson, and M. Doxey. 2007. Management alternatives ments in the North Island, New Zealand. Agriculture the editing of individual manuscripts from the symposium: to enhance water quality and ecological function of Ecosystems and Environment 92:49-69. Ray Bryam (Pasture Systems and Watershed Management channelized streams and drainage canals. journal of Soil Pappas, E.A., and D.R. Smith. 2007. Effects of dredging an Research Unit, USDA Agricululral Research Service), Curt and Water Conservation. 62(4):308-320. agricultural drainage ditch on water coluI1U1 herbicide Dell (Pastllre Systems and Watershed Management Research Gilliam,J.W, R.W Skaggs, and S.B. Weed. 1979. Drainage concentration, as predicted by fluvarium techniques. Unit, USDA Agricultural Research Service), Ed Dunne control to diminish nitrate loss £i'om agricultural fields. Journal of Soil and Water Conservation 62(4):262-268. (Institute of Food and Agriculnlral Sciences, University Journal ofEnvironmental Quality 8:137-142. Penn, CJ., R.B. Bryant, I'J.A. KJeinman, and A.L. Allen. of Florida), Brian Needelman (University of Maryland), Helland, J. 1999. The drainage issue. St. Paul, MN: 2007. Removing dissolved phosphorus from drainage Doug Smith ( ational Erosion Research Laboratory, USDA Minnesota House of Representatives. www.house.leg. ditch water \vith phosphorus sorbing materials. Journal Agricultural Research Service), Jeff Strock (University of state.nUl. us/hrd/pubs/drainage.pdf. ofSoil and Water Conservation 62(4):269-276. Minnesota), and Andy Ward (Ohio State University). We also Hunt, PG., K.C Stone, EJ. Humenik, TA. Matheny, and Pierce, S.C, S.R. Pezeshki, and M.T Moore. 2007. Ditch thank the participants at the event for their many insights M.H. johnson. 1999. In-stream wetland nutigation of plant response to variable flooding: A case study of and contributions. Additional information about this event, nitrogen contamination in a USA coastal plain stream. Lcersin oryzoides (rice cutgrass).Journal ofSoil and Water including symposium presentations and the field tour guide, is Journal ofEnvironmental Quality 28:249-256. Conservation 62(4):216-225. available at http://wv.lw.sawgal.umd.edu/DrainageDitches/ Janse, J.H. 1998. A model of ditch vegetation in relation Portielje, R., and R.M.M. Roijackers. 1995. Primary succes­ 2006DitchTour.html. to eutrophication. Water Science and Technology sion of aquatic macrophytes in experimental ditches in 37:139-149. relation to nutrient input. Aquatic Botany 50:127-'140. References Janse, J.H., and P Van Puijenbroek. 1998. Effects of eurro­ Powell, G.E., A.D. Ward, D.E. Mecklenburg, J. Draper, and Agricultural Drainage Management Coalition. 2007. phication in drainage ditches. Environmental Pollution W Word. 2007a. Two-stage channel systems: Part 2, Owatonna, MN: Agricultural Drainage Management 102:547-552. case studies. Journal of Soil and Water Conservation Coalition. wvvw.admcoalition.com. Jayakaran,A.D.,andA.D.Ward. 2007. Geometry ofinset chan­ 62(4):286-296. nels and the sediment composition of fluvial benches in Agricultural Drainage Management Systems Task Force. Powell, G.E., A.D. Ward, D.E. Mecklenburg, and A.D. agricultural drainage systems in Ohio. Journal of Soil 2007. Columbus, OH: Ohio State University Extension. Jayakaran. 2007b. Two-stage channel systems: Parr 1, http://extension .osu.edu/-usdasdru/ADMS/ and Water Conservation 62(4):296-307. Aapractical approach for sizing agricultural ditches. ADMSindex.htm. Jellick, G. 2006.The Cropper site, Snow Hill, MD: Integrating Journal ofSoil and Water Conservation 62(4):277-286. Barrhelmeh, T, and M. Biddle. 2006. The Haines stream Maryland highway construction \vith the Coastal Bays Rhoderick, J., J. Keppler, WD. Hively, G. McCarty, Program. 11/ Improved Management of Agricultural and wetland restoration project at prong 6 of the T Fisher, and T Jordon. 2006. The Collier farm, Petersburg tax ditch, Felton, DE: Effectiveness of Drainage Ditches for Water Quality Protection: Field Goldsboro, MD: Choptank River watershed study. restored wetlands for the treatment of agriculnlral Tour Guide, ed. B.A. Needelman and S.A. Wills. College III Improved Management of Agriculnlral Drainage Park, MD: University of Maryland. www.sawgal.umd. runoff. III Improved Management of Agricultural Ditches for Water Quality Protection: Field Tour edu/DrainageDitches/2006_tourandsymposium/. Drainage Ditches for Water Quality Protection: Field Guide, ed. B.A. Needelman and S.A. Wills. College Tour Guide, ed. B.A. Needelman and S.A. Wills. College Karr,J.R., and E.W Chu. 1999. 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I JULY IAUGUST 2007 VOLUME 62, NUMBER 4 ~ Water Quality Protection: Symposium. College Park, MD: University of Maryland. www.sawgal.umd. edu/DrainageDitches/2006_tourandsymposium/. Skaggs, R.W, M.A. Breve, and ].W Gilliam. 1994. Hydrologic and water- quality impacts ofagriculcural drainage. Critical Reviews in Environmental Science and Technology 24:1-32. Skaggs, R.W, and].V Schilfgaarde, eds. 1999. Agricultural Hydrology and groundwater nutrient drainage. Agronomy Monograph 38. Madison, WI: American Society ofAgronomy-Crop Science Society ofAmerica-Soil Science Society ofAmerica. concentrations in a ditch-drained Skaggs, R.W, G.M. Chesheir, and B.D. Phillips. 2005a. Methods to determ..ine lateral effect of a drainage agroecosystem ditch on wecland hydrology. Transactions of the ASAE 48:577-584. Skaggs, R.W, A.A. Youssef, G.M. Chescheir, and ].W P.A. Vadas, M.S. Srinivasan, P.J.A. Kleinman, J.P. Schmidt, and A.L. Allen Gilliam. 200Sb. Effect of drainage intensity on nitro­ gen losses from drained lands. Transactions of the ASAE 48:2169-2177. Abstract: Groundwater nitrogen (N) and phosphorus (P) transport from ditch-drained, culti­ Smith, D.R., and E.A. Pappas. 2007 Effect of ditch dredg­ vated fields has not been adequately investigated in the Chesapeake Bay watershed.We moni­ ing on the fate of nutrients in deep drainage ditches of tored hydrology and groundwater Nand P concentrations in 26 shallow (~3 m [10 ft]) wells the Midwestern United States.Journal ofSoil and Water for 27 months on a heavily ditched, poultry-grain farm on Maryland's Lower Eastern Shore. Conservation 62(4):252-261. Water tables fluctuated above and below shallow ditches, but were always higher than deep Smith, D.R., E.A. Warnemuende, B.E. Haggard, and C. Huang. 2006. Dredging of drainage ditches increases ditches.Thus, groundwater flow to shallow ditches was intermittent, but flow to deep ditches short-term transport of soluble phosphorus. Journal of was continuous.Water tables rose rapidly with rain, but drained back from 15 to 60 cm (6 to Environmental Quality 35:611-616. 24 in) the first day after rain. The rate of water table fall decreased rapidly thereafter. Water Stott, R., and c.c. Tanner. 2005. Influence of biofilm on tables frequently perched on top of subsoil clay horizons. Although perching persisted only removal of surrogate faecal microbes in a constructed wetland and maturation pond. Water Science and 24 to 48 hours, nutrient transport could be accelerated ifrapid, lateral movement ofwater to

Technology 51:315-322. ditches occurs. Frequent and widespread concentrations ofgroundwater N03-N greater than Strock,].S., c.]. Dell, and].P Schmidt. 2007. Managing natu­ 10 mg L- 1 show subsurface N loss from the farm is probable. High concentrations ofdissolved ral processes in drainage ditches for nonpoint source P existed in groundwater, but P movement in groundwater was restricted. Rain infiltrating nitrogen controLJournal ofSoil andWater Conservation through topsoils mobilized soil P into groundwater and moved considerably high concen­ 62(4):188-196. Vadas, P.A., M.S. Srinivasan, P].A. Kleililllan,].P Schmidt, and trations of P as deep as 1.5 m (4 ft), where elevated P concentrations persisted for days or A.L. Allen. 2007. Hydrology and groundwater nutrient weeks. Groundwater P concentrations were greatest where high water table hydrology com­ concentrations in a ditch-drained agroecosystem.Journal bined with the greatest soil P concentrations. Delivery of groundwater P to shallow ditches ofSoil and Water Conservation 62(4):178-188. was apparently controlled by near-ditch soil P conditions, while P delivery to deep ditches van Schilfgaarde,]. 1971. Drainage yesterday, today, and tomorrow. 11/ Proceedings of the ASAE National was controlled by how deep groundwater flowed. Therefore, limiting soil P accumulation in Drainage Symposium. St.]oseph, MI: American Society near-ditch zones may help reduce P delivery to shallow ditches, and increasing the length of ofAgricultural Engineers. groundwater flow paths through low-P subsoils may help reduce P delivery to deep ditches. van Strien,A.J.,].Van Der Linden,T.C.P Melman, and M.A.W Noordervliet. 1989. Factors affecting the vegetation of Key words: ditch-drained agroecosystem-groundwater-hydrology-nitrogen concentra­ ditch banks in peat areas in the western Netherlands. Journal ofApplied Ecology 26:989-1004. tion-phosphorus concentrations-water tables van Strien, A.J., T. Van Der Burg, W]. Rip, and R.C.W Strucker. 1991. Effects ofmechanical ditch management on the vegetation of ditch banks in Dutch peat areas. Journal ofApplied Ecology 28:501-513. Nitrogen (N) and phosphorus (P) are nearly 600 million birds at a wholesale value Vaughan, R.E., B.A. Needelman, P.].A. Kleinman, and A.L. ofnearly $2 billion. Nearly all ofthe 750,000 Allen. 2007. Sparial variation of soil phosphorus within the primary nutrients that accelerate a drainage ditch network. Journal of Environmental eutrophication in fresh surface waters tons of poultry manure annually produced Quality 36:1096-1104. (Carpenter et at. 1998). Eutrophication is Vaughan, R.E., B.A. Needelman, P].A. Kleinman, and M.C. an aging process where influxes of nutrients Peter A. Vadas is a soil scien- Rabenhorst. Forthcoming. Morphology and character­ promote excessive plant and algae growth and ization of ditch soils at an Atlantic Coastal Plain farm. tist at the Dairy Forage Research Soil Science Society ofAnlerica Journal. can limit water use for recreation, industry, Center, USDA Agricultural Research Service and drinking. On the Delmarva Peninsula in (ARS), Madison, Wisconsin. M.S. Srinivasan the Mid-Atlantic region ofthe United States is a hydrologist at the Invermay Agricultural (figure 1), the Chesapeake Bay and Delaware Centre, AgResearch limited, Mosgiel, New Zealand. Peter J.A. Kleinman and John P. and Maryland's Coastal Bays are subject to Schmidt are soil scientists at the Pasture Sys­ eutrophication-related algal blooms (Boesch tems and Watershed Management Research et al. 2001; Boynton 2000). Unit, USDA ARS, University Park, Pennsylvania. The Delmarva Peninsula is home to one Arthur L. Allen is an associate professor at the of the most concentrated poultry industries University of Maryland Eastern Shore, Princess in the United States, and annually produces Anne, Maryland.

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