7. Insights from NAEW experiences for establishing new experimental watersheds

Many paths can be followed to establish new experimental watersheds to conduct watershedscience research ("outdoor laboratories for water and land-management research") such as the NAEW. Watershed science involves expertise in the biological and physical sciences to solve national problems. Occasionally required expertise can be acquired from university, government, and private-sector partners and stakeholders. The 81-year experience of managing experimental watersheds may be useful for establishing new experimental sites at the scale of the NAEW, and some important considerations from the NAEW experience are listed below.


3. Monitoring a large experimental watershed requires sufficient funding to sustain scientists, support staff, and experimental resources. The value of experimental watersheds is that they can provide an uninterrupted record of runoff, water quality, etc., spanning years, with dry years producing insufficient numbers of runoff events and longer periods of runoff records may be required. Furthermore, watershed-science research can be considered long-term and high risk because experiments are subject to weather extremes (e.g., droughts and other project factors that are affected by the weather). It is expensive to maintain such a record, and continuous funding must be maintained—temporary grants will interrupt long-term records after the grant period is completed, and a sufficient record of runoff may not be recorded.

Landfills: Lysimeter data validated an engineering design model for a new type of landfill cover that utilized the ET processes in the soil to minimize water percolating to ground water [33]. Other research: Other research conducted at the NAEW (not exhaustive list) were projects related to water quality of spent foundry sand, dairy wastes, and nursery operations. Frozen

Emerging issues: A significant advantage of the NAEW facility is its long-term data base and the permanent monitoring infrastructure. It has been used for many investigations which were never imagined at the outset. Examples are placement of impervious structures for urbanization studies, evapotranspiration landfill caps, macropore investigations, advanced modeling, organic agriculture, climate change, ground-water recharge studies, spent foundry sand, nursery operations, dairy wastes, filter socks, carbon sequestration, pathogens and estrogens in runoff [48], biofuels, surface mining and reclamation, paper mill sludge, and long-term water-

7. Insights from NAEW experiences for establishing new experimental

Many paths can be followed to establish new experimental watersheds to conduct watershedscience research ("outdoor laboratories for water and land-management research") such as the NAEW. Watershed science involves expertise in the biological and physical sciences to solve national problems. Occasionally required expertise can be acquired from university, government, and private-sector partners and stakeholders. The 81-year experience of managing experimental watersheds may be useful for establishing new experimental sites at the scale of the NAEW, and some important considerations from the NAEW experience are listed below. 1. When establishing new experimental watersheds, "representativeness" is important, and newer GIS technology should be used to identify potential sites. However, there will be other research benefits discovered as a facility is managed. In the case of the NAEW, the geological and soil characteristics became important for potentially providing new knowledge on hydrological processes such as nonuniform runoff generation, interflow, macropore flow, perched water tables, etc. Other potential site benefits should be consid-

2. For an ideal comprehensive watershed-science program, the three original NAEW objectives are required. However, funding may become a problem and pursuit of the three objectives can be spread at more than one location (e.g., one location can perform modeling and another field experimentation). However, having modelers conducting field research is also of value to experience data characteristics and natural variability found in landscapes to help formulate algorithms. It is important to have field data for validation of

soil, rain gauges, soil moisture, soil characterization, etc., have also been topics.

quality response times in natural systems.

16 Hydrology of Artificial and Controlled Experiments

watersheds

ered in site selection.

watershed models.


8. Instrumentation selection is important in managing experimental watersheds. Two important measurements are runoff and precipitation. For runoff, it is known that large sediment concentrations in runoff can affect the rating curve of H flumes [51], a commonly used flow-measuring device. A weir that has been tested for a wide range of field conditions under large sediment loads (including rocks) is the drop-box weir [7]. Drop-box weirs of any size can be constructed from small runoff/erosion plots to large watersheds with incised channels. It is important to house weirs from freezing weather to prevent damage and maximize the opportunity for good winter runoff records.

12. It should be recognized that some investigations will be affected by watersheds with low runoff potential (e.g., some forested sites). It may take many years for such watersheds to

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13. Knowledge of challenges in conducting watershed research in disturbed lands in particu-

14. It is highly likely that as an emerging issue arises, that an experimental watershed facility would be a likely place for pertinent investigations. The permanent monitoring infrastructure allows for a relatively rapid implementation of a proposed land treatment and mon-

15. Another opportunity for monitoring experimental watersheds is off site from the home site. This was necessary for monitoring watersheds with three different coal seams in the

16. It is important for all data to be checked and be made available on the internet as soon as

The North Appalachian Experimental Watershed (NAEW), in east-central Ohio near Coshocton, Ohio, was one of the three large watershed facilities established in 1935 to advance watershed science of agricultural lands to improve their economical and physical sustainability. It was an outdoor laboratory for land and water management research. The original objectives were to test management practices on small watersheds (small swales in the hilltops), investigate scaling of runoff and erosion to larger areas, and provide a way to extrapolate the results to ungauged areas (modeling). The NAEW was in an unglaciated sedimentary geological setting (strata nearly horizontal) and originally spanned an area of approximately 2000 ha. The facility was equipped with a permanent infrastructure consisting of runoff stations and rain gauges for watersheds ranging in size from 0.26 to 1854 ha. After about 1970, the NAEW was reduced to a 425-ha area consisting of mostly small watersheds ("test beds") ranging in size from 0.26 to 3.07 ha but with a few up to 123 ha. The smaller watersheds were equipped with the well-known Coshocton Wheel composite runoff samplers. The NAEW was in operation for approximately 81 years with an approximate 79-year record of runoff and other data for various watersheds, and was closed in 2015. Eleven large monolith lysimeters

A wide variety of experiments were conducted on the NAEW with many high impact accomplishments (listed in the section titled, Examples of Accomplishments of the NAEW). Many investigations used the facility for emerging national issues that the founders never envisioned (e.g., surface mining impacts, landfill caps, organic agriculture, climate change, filter socks, carbon sequestration, pathogens in runoff, biofuels). Nearly 500 publications were developed

disturbed land (coal mining) project conducted at the NAEW [58], Figure 11.

provide enough data for evaluations to experience larger infrequent rainfalls.

lar is presented in [58] and is pertinent to selecting new watersheds.

itoring. Funding for such issues is important.

were also constructed to investigate small scale water balances.

from investigations during the 81-year history of the facility.

possible after collection.

8. Summary


### 8. Summary

8. Instrumentation selection is important in managing experimental watersheds. Two important measurements are runoff and precipitation. For runoff, it is known that large sediment concentrations in runoff can affect the rating curve of H flumes [51], a commonly used flow-measuring device. A weir that has been tested for a wide range of field conditions under large sediment loads (including rocks) is the drop-box weir [7]. Drop-box weirs of any size can be constructed from small runoff/erosion plots to large watersheds with incised channels. It is important to house weirs from freezing weather to prevent damage

9. Precipitation measurement is a persistent problem because the gauge shape and orifice height affect the wind flow around the orifice, resulting in an under catch of precipitation. This is because smaller diameter rain drops and light weight snowflakes are carried with the wind away from the orifice. This error can be as high as a 20% under catch on average during the winter and approximately 2% during the nonwinter months [52]. True ground-level precipitation measurements for individual events can be much higher during events with high wind speeds. Furthermore, often-used tipping bucket rain gauges do not measure snowfall, and under catch of precipitation is complicated by using heaters to melt the snow because precipitation is evaporated [53], and snow intensities will not be measured. In arid areas this may not be a problem. The effects of under estimating precipitation are to under estimate runoff, erosion, and water quality in watershed modeling [49] in a nonlinear manner. Suggestions for improved precipitation measurement include shielded gauges such as the dual fence gauge of the Climate Reference Network [54] that was evaluated by US Forest Service [55]. Their study suggested that the CRN gauge is the best available. A set of dual gauges (one shielded and one not shielded) were not tested in the Forest Service study, but is likely to be a contender and should be investigated [56]. Furthermore, weighing buckets are preferred measuring technology compared with tipping buckets. Advances in other emerging

10. Water quality sampling is important for evaluations of the performance of land treatments. Two types of sampling are possible—composite and discrete sampling. For composite sampling, the same fraction of the flow is sampled for each flow rate during the runoff event and only one sample is obtained for the event. The Coshocton Wheel has been a useful tool for composite sampling of small watersheds [6, 39]. Larger watersheds require smaller fractions of flow sampling to manage the size of a composite sample and for a range of runoff volumes. Commercial samplers and the Coshocton Vane sampler [57] are available for this purpose. An instantaneous sample is pumped for discrete sampling a preselected times or changes in runoff depth, and many samples are obtained for an individual event. This type of sampling is more expensive and may not be as useful as composite sampling unless there is a research objective for this sampling strategy. For evaluations of water quality effects of land treatments, a composite sample is adequate (and may be preferred). For either sampling type, a flow measurement record is required.

11. It is possible that experimental watershed investigations can be affected by a changing

climate. Climate was found to be changing at the NAEW.

and maximize the opportunity for good winter runoff records.

technologies should also be explored.

18 Hydrology of Artificial and Controlled Experiments

The North Appalachian Experimental Watershed (NAEW), in east-central Ohio near Coshocton, Ohio, was one of the three large watershed facilities established in 1935 to advance watershed science of agricultural lands to improve their economical and physical sustainability. It was an outdoor laboratory for land and water management research. The original objectives were to test management practices on small watersheds (small swales in the hilltops), investigate scaling of runoff and erosion to larger areas, and provide a way to extrapolate the results to ungauged areas (modeling). The NAEW was in an unglaciated sedimentary geological setting (strata nearly horizontal) and originally spanned an area of approximately 2000 ha. The facility was equipped with a permanent infrastructure consisting of runoff stations and rain gauges for watersheds ranging in size from 0.26 to 1854 ha. After about 1970, the NAEW was reduced to a 425-ha area consisting of mostly small watersheds ("test beds") ranging in size from 0.26 to 3.07 ha but with a few up to 123 ha. The smaller watersheds were equipped with the well-known Coshocton Wheel composite runoff samplers. The NAEW was in operation for approximately 81 years with an approximate 79-year record of runoff and other data for various watersheds, and was closed in 2015. Eleven large monolith lysimeters were also constructed to investigate small scale water balances.

A wide variety of experiments were conducted on the NAEW with many high impact accomplishments (listed in the section titled, Examples of Accomplishments of the NAEW). Many investigations used the facility for emerging national issues that the founders never envisioned (e.g., surface mining impacts, landfill caps, organic agriculture, climate change, filter socks, carbon sequestration, pathogens in runoff, biofuels). Nearly 500 publications were developed from investigations during the 81-year history of the facility.

Experiences in the operation of the facility during the 81 years provide insights for establishing new experimental watersheds in the future. Watershed science involves the expertise in the biological and physical sciences and engineering to solve national problems. Sixteen suggestions for new facilities are presented covering site selection, funding, site specificity, extrapolation of results, generation of runoff in different physiographic regions, collaboration, off-site investigations, and instrumentation. Instrumentation suggestions are particularly important for precipitation because it is a major driver of watershed responses and must be more accurately gauged than commonly measured. Runoff measurements also can be affected by large sediment concentrations using common flow-measuring devices. Watershed modeling will be sensitive to precipitation inputs and validation of runoff amounts in modeling will be affected by runoff measurements.

[4] Ramser CE, Krimgold DB. Detailed working plan for watershed studies in the North Appalachian Region relating to water conservation, flood control, and run-off as influenced by land use and methods of erosion control; 1935. WHS#1, November, 1935 [5] Kelley GE, Edwards WM, Harrold LL, McGuinness JL. Soils of the North Appalachian

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[6] Brakensiek DL, Osborn HB, Rawls WJ. Field Manual for Research in Agricultural Hydrology. U.S. Dept. of Agriculture, Agriculture Handbook No. 224. Washington, DC: U.S.

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[8] Harrold LL, Triplett GB, Youker RE. Watershed test of no tillage corn. Journal of Soil and

[9] Shipitalo MJ, Edwards WM. Runoff and erosion control with conservation tillage and reduced-input practices on cropped watersheds. Soil andWater Tillage Research. 1998;46:1-12

[10] Shipitalo MJ, Owens LB, Bonta JV, Edwards WM. Effect of no-till and extended rotation on nutrient losses in surface runoff. Soil Science Society of America Journal. 2013;77:1329-1337

[11] Edwards WM, Shipitalo MJ, Dick WA, Owens LB. Rainfall intensity affects transport of water and chemicals through macropores in no-till soil. Soil Science Society of America

[12] Shipitalo MJ, Dick WA, Edwards WM. Conservation tillage and macropore factors that affect water movement and the fate of chemicals. Soil & Tillage Research. 2000;53:167-183

[13] Owens LB, Van Keuren RW, Edwards WM. Hydrology and soil loss from a high-fertility, rotational pasture program. Journal of Environmental Quality. 1983;12(3):3441-3346 [14] Owens LB, Van Keuren RW, Edwards WM. Nitrogen loss from a high-fertility, rotational

[15] Owens LB, Bonta JV. Reduction of nitrate leaching with haying or grazing and omission

[16] Owens LB, Shipitalo MJ. Runoff quality evaluations of continuous and rotational overwintering systems for beef cows. Agriculture, Ecosystems & Environment. 2009;129(4):

[17] Owens LB, Barker DJ, Loerch SC, Shipitalo MJ, Bonta JV, Sulc RM. Inputs and losses by surface runoff and subsurface leaching for pastures managed by continuous or rotational

[18] Owens LB, Edwards WM, Van Keuren RW. Baseflow and stormflow transport of nutrients from mixed agricultural watersheds. Journal of Environmental Quality. 1991;20(2):

pasture program. Journal of Environmental Quality. 1983;12(3):346-350

stocking. Journal of Environmental Quality. 2012;41(1):106-113

of nitrogen fertilizer. Journal of Environmental Quality. 2004;33(4):1230-1237

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