Catchment Geology Research Articles

Invertebrate community structure in streams of the Manawatu–Wanganui region, New Zealand: the roles of catchment versus reach scale influences

Summary1. Invertebrate communities at 187 least impacted streams in the Manawatu–Wanganui region of New Zealand were sampled between February and May 2000 to investigate the relative influence of catchment and reach scale environmental influences on community structure.2. Of the 138 biological (fish and periphyton), local habitat and catchment scale descriptors used to examine invertebrate community patterns, alkalinity and conductivity were the most consistently influential predictors.3. Of the 52 geographical information system (GIS)‐derived catchment variables (catchment geology, catchment land use, rainfall and topography) only per cent catchment in pasture, indigenous forest, coastal sand, crushed argillite and wind blown sand were associated with any measures of the invertebrate communities.4. Grouping of communities based on GIS data in general, did not generate distinct community types. Groupings based on river catchment, conductivity and alkalinity however, did produce distinct communities.5. Streams with very low alkalinity were dominated by Ephemeroptera, Plecoptera and Trichoptera that were gradually replaced by Mollusca, Crustacea and Chironomidae as alkalinity increases.6. Habitat characteristics measured at the scale of the reach were more closely linked with measures of invertebrate community structure than any GIS derived variables or river classifications.

Spatial variation in fine sediment transport in small upland streams: the effects of flow regulation and catchment geology

AbstractIn cobble‐ and gravel‐bed streams, fine sediments (<4 mm diameter) are an important component of the bed material that can move at a full range of flows, not just during floods and spates. It has been hypothesized that the constant movement of this fine material, as it passes over the coarse bed, is an important ecological disturbance to plants and animals. In this study, I measured baseflow sediment transport rates across a number of regulated and unregulated sites in an upland catchment comprising isolated regions of granite/sandstone and acid volcanics in southern Victoria, southeastern Australia, as a precursor to a study examining the effects of sediment on aquatic biota. Examined on three separate occasions, transport rates for fine sediments were up to 100 times greater in the granite/sandstone streams, but diversion weirs, which greatly reduced downstream sediment loads in the granite/sandstone areas, moderated these differences. Measured transport rates within unregulated sections of the granite/sandstone streams were roughly equivalent to sediment loads found to disturb benthic communities in other experimental studies. On this basis, abrasion by sediment transport in these streams may be sufficient to influence the structure of benthic communities even at baseflow. This hypothesis forms the basis of other research examining the biota at these sites. Copyright © 2004 John Wiley & Sons, Ltd.

Using tracers to upscale flow path understanding in mesoscale mountainous catchments: two examples from Scotland

Natural geochemical tracers were monitored over a hydrological year in the Feshie (231 km 2) and Feugh (233 km 2) catchments in the Cairngorm Mountains, Scotland. The monitoring sought to assess the utility of tracers in upscaling flow path understanding in mesoscale catchments. A spatially and temporally nested sampling approach was adopted involving hydrochemical monitoring of sub-catchments ranging from 1 to ≈100 km 2 in area. This allowed chemically-based hydrograph separations to be made and faciliated catchment-wide prediction of stream chemistry at a high and low flows. Differences in catchment geology were the main controls on baseflow chemistry, which was spatially variable in both catchments. However, acidic, organic soils produced the majority of storm runoff at all scales monitored, though its contribution was determined by the soil distributions of particular sub-catchments. Given the practical difficulties associated with comprehensive hydrometric monitoring at large spatial scales, it is argued that focused tracer studies can provide both an invaluable insight into the hydrological functioning of mesoscale catchments and a useful additional method for evaluating the structure and performance of distributed hydrological models. In addition, such tracer data provides important information on hydrological pathways that can aid catchment management.

Relative Influences of Catchment Geology, Land Use and in-Stream Habitat on Brown Trout Populations in South-Western Ireland

Salmonid populations were sampled in 36 streams, at altitudes between 10m and 200m, in counties Cork and Kerry, south-western Ireland. The catchment land use ranged from open moorland and rough pasture/improved grassland to afforested sites with varying levels of catchment afforestation, mostly coniferous but with some patches of mixed coniferous and deciduous trees. The main geology types within the region were slate, Old Red Sandstone and limestone. Study sites were electrofished, and the density, biomass, age structure and condition of salmonid populations were assessed. A range of in-stream riparian and catchment environmental variables were measured, and the data were analysed using stepwise multiple regression to identify the most influential environmental factors affecting trout metrics following principle component analysis. The majority of salmonids were trout (86%), and mean trout density ranged from 0.662 fish mto 0.984 fish m-2 for all sites, irrespective of catchment geology. Trout condition did not differ significantly with level of catchment afforestation or geology, with the exception of limestone with high catchment afforestation. At sites with underlying limestone, trout condition decreased with increased catchment afforestation. River habitat structure was identified as the most important variable influencing trout density and biomass, irrespective of geology and water chemistry.

Relative Influences of Catchment Geology, Land Use and In-Stream Habitat on Brown Trout Populations in South-Western Ireland

Salmonid populations were sampled in 36 streams, at altitudes between 100m and 200m, in counties Cork and Kerry, south-western Ireland. The catchment land use ranged from open moorland and rough pasture/improved grassland to afforested sites with varying levels of catchment afforestation, mostly coniferous but with some patches of mixed coniferous and deciduous trees. The main geology types within the region were slate, Old Red Sandstone and limestone. Study sites were electrofished, and the density, biomass, age structure and condition of salmonid populations were assessed. A range of in-stream riparian and catchment environmental variables were measured, and the data were analysed using stepwise multiple regression to identify the most influential environmental factors affecting trout metrics following principle component analysis. The majority of salmonids were trout (86%), and mean trout density ranged from 0.662 fish m⁻² to 0.984 fish m⁻² for all sites, irrespective of catchment geology. Trout condition did not differ significantly with level of catchment afforestation or geology, with the exception of limestone with high catchment afforestation. At sites with underlying limestone, trout condition decreased with increased catchment afforestation. River habitat structure was identified as the most important variable influencing trout density and biomass, irrespective of geology and water chemistry.

Trace elements in freshwater ecosystems in the Canadian Arctic

The expedition Tundra North West 99 visited 17 sites across the Canadian Arctic in order to sample freshwater, sediments, soil and biotic compartments of the ecosystems. Trace metal concentrations were determined using ICP-MS. Dating of sediment profiles using 137 Cs showed a very low sedimentation rate in these lakes (<1 mm/yr). The lake waters were mostly well buffered with high pH and hardness, with the exception of lakes on Ellef Ringnes Island and Baffin Island. Trace metal concentrations in lake waters were generally low, but with some locally elevated concentrations. Trace metal profiles in sediments showed influence of catchment geology, indicated by elevated concentrations at some sites, e.g. NW Yukon. Increased concentrations of Cd, Hg, Zn, Pb, Tl and some other elements, found in recent sediment layers may indicate long-range airborne pollution. The elevated concentrations of e.g. Cd and Cu in the sediments and water at the Yukon site were also reflected in fish. Cd-concentrations in Arctic char liver were about 10 times higher than in other areas in the Arctic and in northern Sweden. Cd-concentrations in char liver were otherwise low with slightly elevated values in the more soft water lake at Baffin Island. Mercury concentrations in sediment at the Yukon site were 20-40 times higher than in the other lakes, whereas the concentration in fish muscle were still not elevated, which may be explained by the also elevated Se concentrations in the lake. The variations in Hg-concentrations in Arctic char were otherwise small, with the highest values at Ungava Peninsula and Ellesmere Island.

Typological and qualitative characteristics of Greek-interregional rivers

The catchments of the interregional rivers (I.R.) entering Greece cover an area of approximately 98000 km2, of which only 14% belongs to Greece, while their contribution to the country’s freshwater runoff reach 40% (18 km3/a). Geologically, the I.R. catchments are marked by their high percentage of acid silicates. I.R. show hydrochemical similarities, except for Evros, which is highly polluted. Compared to the other major Greek rivers, I.R. are the most polluted, with the Evros at the top, followed by the Axios. The main factors controlling their composition are climate, pollution and catchment geology. Inter-annual qualitative variations are controlled by seasonal climatic variations, which govern evaporation, groundwater contribution to river flow, dilution and flushing. A long-term salinisation of river water is attributed to climatic and anthropogenic impact. The I.R. transfer approx. 6,63 Μ t dissolved solids to the sea annually. Regarding the inputs of pollutants into the sea, they transfer over 70 % of the potassium, nitrate and dissolved organic carbon of the total load carried by major Greek rivers (78% of total Greek surface runoff), whereas for phosphate and sulphate the percentages reach 89 and 78.

P, As, Sb, Mo, and other elements in sedimentary Fe/Mn layers of Lake Baikal.

Distinct layers with accumulated iron and manganese oxyhydroxides are found in the recent sediments of Lake Baikal (Siberia). In the South and Central Basins, these concretions accumulate close to the sediment-water interface. In northern Lake Baikal and the area of Academician Ridge, however, massive Fe/Mn crusts are formed within several thousand years at redox fronts 10 to 15 cm below the sediment surface. In some places, precipitated iron and manganese oxyhydroxides are spatially separated. The patterns are a result of secondary iron and manganese oxide precipitation. This natural long-term experiment allows the analysis of competitive adsorption and coprecipitation of trace elements with iron and manganese oxides in sediments. Background concentrations in the sediment of oxoanions (P, As, Sb, Mo); of trace metals (Cr, V, Cu, Zn, Cd, Pb); and of Mg, Ca, Sr, La, Ce, Pr, Nd, and Sm were analyzed by inductively coupled plasma mass spectrometry. Despite the differences in catchment geology of the many tributaries, they are remarkably uniform in sediment cores from different basins of Lake Baikal. Enrichment factors of P and As within Fe crusts revealed concentrations up to 14 and 58 times higher than the background, respectively. No enrichment of P and As was found in the Mn layers. By contrast, Mo accumulated exclusively in the Mn layer with up to 35-fold enrichment. Sb was only slightly enriched in both the Fe and the Mn layers. Among the trace metals studied, only Cd was found at elevated concentrations with a preference for the Mn layer. Ca and Sr were correlated with both Fe and Mn accumulations. The study quantifies the well-known specific adsorption and coprecipitation of P and As at authigenic iron oxides and of Mo on manganese oxides. In addition, the enrichment of Cd at manganese oxides in contrast to the conservative behavior of Zn and Pb reveals highly selective accumulation processes.

Metals in tissues of European otters ( Lutra lutra) from Denmark, Great Britain and Ireland

Samples of livers of European otters from Denmark, Great Britain and Ireland were analyzed for manganese, chromium, zinc, copper, nickel and cobalt. Concentrations were generally significantly higher in samples from Great Britain. It was considered that this reflected the catchment geology from where the specimens originated.

Isotopic compositions of strontium in river water of Guizhou karst areas, China

We have carried out a study on the variation of strontium isotope composition of river waters, Wujiang and Yuangjiang River, in karst areas of Guizhou Province, China. The results obtained permit us to characterize the geochemistry of the river draining karst terrain and obtain a better understanding of main controls of catchment geology, chemical weathering of different rocks, and evaluate impact of human activities on the environment. The isotopic ratios of dissolved Sr in all rivers are between87Sr/86Sr=0.7077 and 0.7110, totally lower than the weighted average of87Sr/86Sr=0.7119 for the world large rivers. The Wujiang River waters have Sr concentrations from 1.0 to 6.1 μmol/L, while the Yuanjiang River waters have much lower Sr concentrations ranging from 0.28 to 1.3 μmol/L. Most of the river waters from the Wujiang river are characterized by low Ca/Sr and Mg/Sr, and87Sr/86Sr ratios, in which a majority of river waters are of87Sr/86Sr ratios lower than the average Sr isotope ratio (87Sr/86Sr=0.709) of present seawater. The higher87Sr/86Sr ratios are observed in the river waters in the lower reach of the Wujiang River, where the lithology is dominated by detrital rocks and dolomite. The water from Yuanjiang River show higher Ca/Sr, Mg/Sr and87Sr/86Sr ratios due to weathering of silicates, as compared to the river waters from Wujiang river.

Manganese and land-use in upland catchments in Scotland

Manganese (Mn) in surface waters is a micronutrient, but elevated concentrations are toxic to fish and impair drinking water quality. In Scotland, undesirable Mn concentrations (>0.05 mg l−1) occur predominantly in upland freshwaters because the acidic pH and organic nature of catchment soils favour Mn mobilisation. The relationship between upland land-use in Scotland and Mn concentrations in surface waters is reviewed. Conifer afforestation is associated with enhanced Mn in runoff. Mn is leached from conifer foliage and litter, and mature conifers enhance acid deposition and loss of Mn from acidified catchment soils. After harvesting, increased soil pools of water-soluble Mn and elevated Mn concentrations in runoff have been observed. Liming, fertiliser addition, drainage ditch construction and ploughing to improve upland pastures, and muirburn on grouse moors may also increase Mn concentrations in runoff, but the evidence is less clear-cut. The extent to which land-use influences Mn concentrations in upland catchments in Scotland is modified by catchment hydrology and soil type. Catchment geology, instream processes and standing water stratification are probably lesser influences on Mn concentrations in surface waters of upland catchments in Scotland. The location of land-use in upland catchments, especially in the riparian zone, is critical in determining its effect on Mn in runoff. Climate change is expected to increase Mn concentrations in runoff from upland catchments in Scotland because of predicted changes in soil hydrology.

Relationships between stream water chemistry and catchment geology in a mountainous region in Nagano Prefecture, Japan II: mid to southern part along the Median Tectonic Line

Major ion concentrations were determined for a large number of stream water samples collected from the mountainous area around the Median Tectonic Line (MTL) in the mid to southern part of Nagano Prefecture, Japan. The MTL, a major fault in the accretionary sedimentary complex to Japan Arc, extending linearly in the east–west direction in southwest Japan, bends in this area to south–north along the Akaishi Mountain chain. To the east of the MTL are, in order, Jurassic metamorphic rocks, including black/green schists and ultra-basic serpentinite (Sambagawa-Mikabu Belt); Jurassic mudstone with voluminous chert and calcite (Chichibu Belt); and Cretaceous sandstone (Shimanto Belt). On the other hand, on the west side of the MTL, Cretaceous granitic rocks (including tonalite and quartzdiorite) intruded and significantly metamorphosed the Jurassic sedimentary systems (Ryoke-Belt). In this area, more than 200 water samples were collected from small streams. Ion concentrations were analyzed by ion chromatography, whereby higher ion concentrations relatively rich in Mg2+ and Ca2+ and lower concentrations relatively rich in Na+ were obvious for the streams in Sambagawa-Mikabu, Chichibu, and Ryoke Belts, respectively. These tendencies could be explained by whole rock analysis on XRF (X-ray fluorescence spectrometry) as well as by a preliminary leaching experiment of the powdered rock samples with water. The results strongly suggested that the analytical data of the major ions in the stream waters might be compiled into a hydrogeochemical map, corresponding to the geological map.

The influence of catchment geology on the longitudinal distribution of macroinvertebrate assemblages in a groundwater dominated river

The influence of catchment geology on the longitudinal distribution of macroinvertebrate assemblages in a groundwater dominated river

The influence of catchment geology on the longitudinal distribution of macroinvertebrate assemblages in a groundwater dominated river

Macroinvertebrate fauna were collected from 15 reaches along the length of the River Frome, a lowland groundwater-dominated river in Dorset, southern England. The Frome arises in Upper Greensand and Gault Clay before flowing through Chalk and finally Tertiary deposits of gravel and sand. Sampling took place in the summer of 1995 and identification was taken to family level. The relation between longitudinal changes in the faunal assemblages and geology in the catchment was examined using multivariate methods. A preliminary classification of all sites was carried out using TWINSPAN analysis. The 15 sites separated into four distinct groups with all three replicates from any one site always found in the same group. Group I (comprising only the headwater site) and Group IV were associated with the mixed Upper Greensand geology, Group II with Chalk and Group III with the Tertiary gravels. These data were supported by a separate correspondence analysis and would appear to show a pattern between geology in the catchment and the distribution of fauua. However, because the geological changes along the Frome valley occur sequentially downstream, it is not possible to separate geological effects from factors related to position downstream.

Major, Minor and Trace Elements in Surficial Sediments from the Open Adriatic Sea: A Regional Geochemical Study

The concentrations and distributions of major (Al, Ca, Fe, K, Mg), minor (Mn, P, Ti), and trace elements (Ag, As, Ba, Be, Co, Cr, Cu, Ag, La, Ni, Pb, Sc, Sr, Th, U, V, Zn, Zr), in the surficial sea bottom sediments were studied in an attempt to establish their distribution in the Adriatic Sea. Results indicate that major, minor and several trace elements are strongly related to the catchment geology, their distribution being essentially controlled by the type of sediments. However, the majority of trace elements are believed to have been introduced into the Adriatic from the riverine inflows that are also affected by the impact of industrial, mining and urban wastes. Other sources of these elements are located along the coast. The highest concentrations for several trace elements were thus recorded from the coastal ecosystems and from the most polluted Albanian and Italian rivers. The concentrations of trace elements generally decrease with distance from the coast. The regional distribution patterns are influenced by the counter-clockwise system of the Adriatic Sea currents which carry these elements away from the riverine inflows. Correlation analysis indicates that the trace elements are largely associated with the clay minerals, Fe and P contents rather than with the Mn concentrations. Magnesian minerals are suggested as the carrier for some trace elements (As, Co, Cr, Ni, Se and V) only in the southern Adriatic, which reflects their ophiolitic origin in the Albanian hinterland. Organic matter concentrations does not considerably influence the abundance and distribution of trace metals.

Formula omitted] enrichment in agricultural catchments: field patterns and applications to tracking Atlantic salmon ( Salmo salar)

Nitrogen isotopes were used to study the source of nitrate and its uptake into the food web of a northeastern river in Vermont, USA. In six tributaries of the White River (Vermont) nitrate concentrations were elevated in streams flowing through areas with agricultural land use as compared to streams flowing through pristine forested areas. We observed a strong positive correlation between δ 15N values of stream water nitrate and percent of agricultural land-use within a given catchment. Agricultural sites had relatively high δ 15N values of nitrate (+7.3‰) compared to forested sites (+2.0‰). These relatively high δ 15N values coupled with relatively high concentrations of nitrate in agricultural streams suggest the introduction of 15 N -enriched nitrate draining from agricultural areas. Additionally, elevated δ 15N values of algae, aquatic insects, and Atlantic salmon ( Salmo salar) in agricultural sites compared to lower δ 15N values of their counterparts in forested sites suggest the uptake of nitrate from agricultural sources by stream organisms. We observe a similar positive correlation between the δ 15N of Atlantic salmon and the percent of agricultural land in a catchment. The nitrogen isotope values of both Atlantic salmon and water nitrate reflect land-use. Thus, nitrogen isotope ratios in salmon, especially when coupled with strontium isotope ratios (which reflect catchment geology), create unique isotopic identities for Atlantic salmon stocking streams and thereby provide a means of determining the natal origin of juvenile salmon.

Some Peculiarities of Mn Distribution in the Adriatic Sea

The Adriatic as a modem epicontinental sea is situated between the eastern Italian coast and the western coast of Slovenia, Croatia, Jugoslavia and Albania. The results of a regional geochemical study indicate that major, minor and several trace elements are closely related to the catchment geology, following the type of sediment and prevalent currents. Their distribution 9 pattern is affected by the morphological characteristics of the sea-bottom, anthropogenic impact and local hydrological and physicochemical conditions (Dolenec et al., 1998, in press). The present study deals with some peculiarities of Mn distribution in surficial sea bottom sediments from the Adriatic Sea, especially in the Jabuka Pit, which represents the deepest (up to 275 m deep) part of the central Adriatic (Fig. 1).

Hydrologic Influences on Groundwater-Surface Water Ecotones: Heterogeneity in Nutrient Composition and Retention

The groundwater-surface water (GW-SW) ecotone, or hyporheic zone, is an active component of stream ecosystems that influences whole-system metabolism and nutrient retention. Because hydrologic fluxes affect the supply of carbon, nutrients, and oxygen to the GW-SW ecotone, the biogeochemical structure of the ecotone (i.e., nutrient content) and the role of the ecotone in nutrient retention are expected to vary under differing hydrologic conditions. In this paper, we employ an inter-basin comparison of headwater streams to assess the influence of ecosystem hydrology on the structure and functioning of GW-SW ecotones. Specifically, we address how differing rate and extent of GW-SW interaction influences heterogeneity in interstitial nutrient content and how variation in GW-SW interaction alters the role of the ecotone in whole-system nutrient retention. A multiple regression model derived from 6 solute-injection experiments identified the extent and rate of hydrologic exchange between the stream and its aquifer as critical variables that determine the retention of biologically important solutes. This approach emphasizes that the nature of GW-SW interaction is established by catchment geology (i.e., alluvial hydrogeologic properties), is modified by changing discharge within a catchment, and is a strong determinant of nutrient retention. At the landscape scale, identifying catchment geologic composition may be a starting point for comparative studies of GW-SW ecotones that could contribute to a more robust model of lotic ecosystem functioning.

The Høylandet area - patterns and processes of a pristine boreal-subalpine ecosystem : a synopsis

The research activities on soil–freshwaterinteractions and freshwater biotic structure andprocesses in the Hoylandet area during the years 1986–89are presented in this issue ofHydrobiologia. The 9 papers cover a range of topicsfrom physiochemical gradients and processes in soilsand freshwaters to selected aspects of freshwaterbiotic community structure and temporal variability.This synopsis aims (a) to present an overview of majorfindings, (b) to interpret the results in the contextof air pollution effects and (c) to outlinesuggestions for future research activities inHoylandet. The area has a sub-oceanic climate varyingfrom 1100 to 2200 mm of precipitation normallyoriginating from unpolluted airmasses from the NorthAtlantic. It is chemically dominated by sea salts, haslow concentrations and low deposition of mineralacids. The catchment geology is variable and complexand consists mainly of various granites and gneisses.The soils are undisturbed ’ancient‘ soils,primarily iron podzols associated with forests, orintact histosols with strong organic characterassociated with mires, often quite acidic.They are sensitive because occurrence of predominantlyinsoluble unstable Al-complexes may leach out ifexposed to anthropogenically acidified soil drainagewater and turn up as toxic inorganic aqueous Al insurface runoff. Small amounts of locally generatednitrogen compounds are mostly retained in thecatchment. The water qualities of these Hoylandetsites are run by inputs of sea salts, hydrologicalprocesses including dilution of the base flow, orlateral surface or overland flow and in-catchmentprocesses. Relative to affected areas, it appears thatthe inputs and catchment processes are in balance,i.e., that the inputs of strong acid anions, hydrogenions and sea salts are equilibrated by internalweathering and other processes and integrated withinapparently intact biogeochemical cycles. The overallresult is that these soils remain a net source ofalkalinity to the runoff. These results are confirmedby regional studies of water quality both at low andhigh flow which show that the humus and ionic contentof the water decreased with elevation, headwatersbeing more dominated by sea salts and dilutionprocesses. Excess sulphate concentrations are low, andfew if any sites appear anthropogenically acidified,the most acid pH‘s reflecting presence of natural weakorganic acids.

The contribution of flood disturbance, catchment geology and land use to the habitat template of periphyton in stream ecosystems

SUMMARY1. Periphyton chlorophyll a (chl a), ash‐free dry mass, taxonomic composition, and cellular and water‐column nutrients were analysed every 4 weeks for a year at sixteen stream sites in New Zealand. The hypothesis was investigated that broad‐scale differences in mean monthly periphyton development are defined primarily by the frequency of flood disturbances and the periphyton's interaction with the nutrients. it us of the streams as determined by catchment geology and land use.2. Overall, mean monthly chl a concentration declined with increasing flood frequency (r= ‐0.711, P &lt; 0.001), and seasonality in chl a was better defined at sites with a low frequency of floods. Chlorophyll a concentration was generally low throughout the year at sites with frequent floods (&gt; 15 yr−1).3. No relationship existed between inorganic nutrient concentrations and catchment geology or land development. However, conductivity declined significantly as a function of the percentage of the catchment underlain by nutrient‐poor, hard rocks (plutonic and fine‐grained metamorphic rocks) (r= ‐0.515, P &lt; 0.05), but increased significantly with the percentage of the catchment in intensive agricultural land use (r= 0.799, P &lt; 0.001).4. Cellular nutrient concentrations suggested that nitrogen was the nutrient most commonly limiting periphyton production. In turn, cellular N concentrations declined significantly with increasing percentage of the catchment in hard rock (r= ‐0.5M, P &lt; 0.05) and increased with percentage of the catchments in intensive agricultlural land use (r= 0.948, P &lt; 0.001).5.The sites were classified into three enrichment groups (high, moderate and low) based on their land use and underlying geology. Cellular N concentrations varied significantly among these enrichment groups (ANOVA F= 14.661, P &lt; 0.001).6. Log chl a decreased significantly with increases in the annual 80th percentile velocity. However, the relationship was significantly different among the enrichment groups.7. A stepwise multiple regression on the full dataset identified that the frequency of floods, proportion of the catchment in high‐intensity agricultural land use and proportion in alkaline rocks were the most significant factors explaining variation in mean monthly chl a among the sites (r2= 89%).8. Overall, the results showed that flood disturbance and catchment enrichment regimes are probably the principal axes of the habitat template of periphyton among the study streams, and could be used to explain and predict broad‐scale differences in periphyton development among other temperate stream ecosystems.